BR112017014667B1 - METHODS FOR EXTRACTING AND CONVERTING HEMICELLULOSE SUGARS - Google Patents

Abstract

METHODS FOR EXTRACTING AND CONVERTING SUGARS FROM HEMICELLULOSE. The present disclosure relates to systems, methods, and processes for producing sugars and biomass conversion products.

Description

CROSS REFERENCE TO RELATED ORDERS

[0001] This application claims the benefit of United States Provisional Application No. 62/100,791, filed January 7, 2015, and United States Provisional Application No. 62/249,801, filed November 2, 2015, each incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

[0002] Lignocellulosic biomass is an abundant renewable material that has long been recognized as a potential feedstock for producing chemicals, fuels, and materials, including polyol sugar substitutes such as Xylitol. Lignocellulosic biomass mainly comprises cellulose, hemicellulose, and lignin. Efficient and cost-effective processes to extract, separate and refine sugars from biomass are still a challenge.

[0003] Xylitol is a five-carbon sugar alcohol that has favorable properties as a sugar substitute, including low caloric content, good gastrointestinal tolerance, and nearly insulin-independent metabolism in humans. Traditionally, Xylitol is produced by chemically hydrogenating a monosaccharide mixture containing xylose in the presence of a metal catalyst such as Raney Nickel, requiring specialized and expensive equipment for the high pressure and temperature requirements of the reaction. Hydrogenation is non-specific, and produces polyols of other monosaccharides present in the reaction mixture that are difficult and costly to separate from the desired Xylitol product. Traces of metal are undesirable and must also be removed from the product. Altogether, this costly and inefficient process produces Xylitol in only 40-60% yield. Some basic research has been carried out towards the development of bioprocesses for the production of Xylitol, but reasonable yields can only be obtained using pure D-xylose as a feedstock.

SUMMARY OF THE INVENTION

[0004] As such, there is a pressing need for a method of selecting suitable sugar streams for Xylitol production. The present disclosure responds to this need by providing methods, systems, and compositions for producing Xylitol from lignocellulosic biomass. Lignocellulosic biomass can be processed and refined to produce hemicellulose sugar streams, and streams suitable for conversion to selected Xylitol. This allows efficient and cost effective production of Xylitol from renewable sources on an industrial scale.

[0005] In one aspect, the disclosure provides a method of producing Xylitol from a lignocellulose-containing biomass. In one embodiment, the method comprises: (i) fermenting a refined hemicellulose sugar stream to produce a fermentation broth comprising Xylitol; and (ii) recovering Xylitol from the fermentation broth, in which the refined hemicellulose sugar stream was produced by a process comprising: (a) extracting hemicellulose sugars from the biomass, thereby obtaining a stream of hemicellulose sugar and a residual stream of lignocellulose; (b) contacting the hemicellulose sugar stream with an amine extracting agent to form a mixture; and (c) separating from the mixture an organic stream comprising the amine extracting agent, and at least one impurity and the refined hemicellulose sugar stream. Optionally, the biomass is selected from hardwood, wood pulp, bagasse, sugar cane leaves, birch, eucalyptus, corn cobs, corn straw, peanut hulls, grass, and wheat straw such as bagasse. and sugar cane leaves.

[0006] In some examples, the method additionally comprises reduction of ash and soil content of the biomass prior to extraction of hemicellulose sugars from the biomass. Optionally, the reduction comprises one or more stages of slurrying, washing, and dehydrating the biomass. In some examples, the extraction of sugars from hemicellulose comprises hot water extraction. Optionally, the hot water extraction further comprises an acid, such as an inorganic acid. In some examples, the acid is present in an amount of up to 2% weight/weight. Optionally, the extraction takes place at a temperature of 100 to 200 °C.

[0007] In some examples, the amine extracting agent comprises an amine and a diluent. Optionally, the amine comprises at least 20 carbon atoms, such as trilaurylamine. Optionally, the diluent comprises an alcohol, such as hexanol or 2-ethyl-1-hexanol. In some examples, the diluent comprises a C6-12 monoalcohol, kerosene, or a mixture thereof. In some examples, the at least one impurity is selected from ash, acid soluble lignin, furfural, fatty acids, inorganic acids, organic acids, methanol, proteins, amino acids, glycerol, sterols, resin acid, and waxy materials.

[0008] In some examples, the fermentation broth further comprises a microorganism selected from naturally occurring bacteria, recombinant bacteria, naturally occurring yeast, recombinant yeast, and fungi, such as an E. coli strain. Optionally, the fermentation produces, in less than 80 hours, at least 60 grams of Xylitol per liter of fermentation broth, such as at least 100 grams of Xylitol per liter of fermentation broth. Optionally, fermentation produces Xylitol at a rate of at least 1 g/L/hr. In some examples, the fermentation broth comprises less than 1 gram of ethanol per liter.

[0009] In some examples, at least 70% of xylose in the biomass is converted to Xylitol. Optionally, the xylose content of the refined hemicellulose sugar stream is at least 80% of the xylose content of the hemicellulose sugar stream. In some examples, the fermentation does not comprise xylose purified by crystallization. Optionally, the refined hemicellulose sugar stream comprises at least 50% xylose weight/weight relative to total dissolved sugars, such as between 50 and 90% xylose weight/weight relative to total dissolved sugars.

[0010] In one aspect, the disclosure provides a method for producing Xylitol by fermenting a refined hemicellulose sugar stream derived from a lignocellulosic hydrolyzate. In one embodiment, the method comprises converting xylose in the refined hemicellulose sugar stream to Xylitol through fermentation by a microorganism, wherein the refined hemicellulose sugar stream comprises: 50 to 90% xylose weight/weight relative to total dissolved sugars , less than 200 ppm of calcium and furfural in an amount up to 1000 ppm. In some examples, the microorganism is selected from naturally occurring bacteria, recombinant bacteria, naturally occurring yeast, recombinant yeast, and fungi, such as strain E. coli. Optionally, the fermentation produces, in less than 80 hours, at least 60 grams of Xylitol per liter of fermentation broth, such as at least 100 grams of Xylitol per liter of fermentation broth. Optionally, fermentation produces Xylitol at a rate of at least 1 g/L/hr. In some examples, the fermentation broth comprises less than 1 gram of ethanol per liter.

[0011] In practicing any of the methods described herein, the refined hemicellulose sugar stream may comprise less than 5% weight/weight oligomers relative to total dissolved sugars. Optionally, the refined hemicellulose sugar stream comprises arabinose in an amount of up to 12% weight/weight relative to total dissolved sugars, such as between 3 and 12% arabinose weight/weight relative to total dissolved sugars. Optionally, the refined hemicellulose sugar stream comprises at least 10% hexoses weight/weight relative to total dissolved sugars, such as between 10 and 45% hexoses weight/weight relative to total dissolved sugars. Optionally, the hexoses comprise glucose, galactose, mannose, and fructose. In some examples, glucose and fructose comprise at least 50% weight/weight of the hexoses. Optionally, the ratio of xylose to hexoses is between 1.5:1 and 5:1 weight/weight. Optionally, the refined hemicellulose sugar stream comprises disaccharides in an amount of up to 8% weight/weight relative to the total dissolved sugars. Optionally, the refined hemicellulose sugar stream comprises ash in an amount of up to 0.25% weight/weight. Optionally, the refined hemicellulose sugar stream comprises phenolic compounds, in which the phenolic compounds are present in amounts of less than 200 ppm. Optionally, the refined hemicellulose sugar stream comprises furfural in an amount of up to 200 ppm. Optionally, the refined hemicellulose sugar stream comprises less than 200 ppm of calcium. Optionally, the refined hemicellulose sugar stream comprises nitrogen in an amount up to 1000 ppm.

[0012] In one aspect, the disclosure provides a system for producing Xylitol from a lignocellulose-containing biomass. In one embodiment, the system comprises: (i) a hemicellulose extraction unit configured to extract and hydrolyze hemicellulose from biomass to produce a hemicellulose sugar stream and a lignocellulose remnant stream; (ii) a refining unit in fluid communication with an extraction unit, in which the refining unit is configured to receive the hemicellulose sugar stream and an amine extracting agent, and in which the amine extracting agent removes impurities from the hemicellulose sugar stream to produce a refined hemicellulose sugar stream; (iii) a detection unit configured to analyze one or more parameters of the refined hemicellulose sugar stream; (iv) a fermentation unit in fluid communication with the refining unit to receive the refined hemicellulose sugar stream, in which the fermentation unit is configured to contain the refined stream and a microorganism, and in which the microorganism facilitates the Xylitol production of a monosaccharide in the refined stream to produce a fermentation broth; and (v) a Xylitol refining unit, in which the Xylitol refining unit is configured to remove Xylitol from the fermentation broth. In some examples, the system further comprises a scrubbing unit configured to remove ash and soil from the biomass, in which the hemicellulose extraction unit is in fluid communication with the scrubbing unit.

[0013] In some examples, at least 90% of the xylose in the refined hemicellulose sugar stream is converted to Xylitol in the fermentation unit. Optionally, Xylitol is produced at a rate of at least 1 g/L/h in the fermentation unit. Optionally, the fermentation broth comprises less than 10 g/L ethanol, such as less than 4.5 g/L ethanol, optionally less than 1 g/L ethanol. In some examples, the biomass is selected from sugarcane bagasse and leaves, or a combination thereof. In some examples, one or more parameters are selected from pH, light absorbance, conductivity, density, xylose concentration, and hexose concentration.

[0014] In one aspect, disclosure provides a raw material for fermentation. In one embodiment, the fermentation feedstock comprises: (i) 50 to 90% xylose weight/weight relative to total dissolved sugars; (ii) 10 to 45% weight/weight hexoses relative to total dissolved sugars; (iii) arabinose in an amount of up to 12% weight/weight relative to total dissolved sugars; (iv) disaccharides in an amount of up to 8% weight/weight relative to total dissolved sugars; (v) furfural in an amount up to 1000 ppm; and (vi) less than 200 ppm calcium. Optionally, the raw material further comprises (vii) less than 1000 ppm of acetic acid; and (viii) less than 1000 ppm formic acid. In some examples, the starting material additionally comprises a microorganism. In another embodiment, the fermentation feedstock comprises: (i) 50 to 90% xylose weight/weight relative to total dissolved sugars; (ii) less than 200 ppm calcium; (iii) furfural in an amount up to 1000 ppm; and (iv) a microorganism. Optionally, the raw material additionally comprises 10 to 50% of hexoses weight/weight relative to the total dissolved sugars. Optionally, the raw material additionally comprises arabinose in an amount of up to 12% weight/weight relative to the total dissolved sugars. Optionally, the raw material additionally comprises disaccharides in an amount of up to 8% weight/weight relative to the total dissolved sugars. Optionally, the raw material additionally comprises less than 1000 ppm of acetic acid. Optionally, the raw material further comprises less than 1000 ppm of formic acid. In some examples, the feedstock further comprises a C6-12 monoalcohol in an amount of up to 100 ppm. In some examples, the raw material additionally comprises nitrogen in an amount of up to 1000 ppm.

[0015] In one aspect, disclosure provides a fermenting broth. In one embodiment, the fermentation broth comprises: (i) at least 60 g/L Xylitol; (ii) less than 10 g/L of ethanol; (iii) xylose in an amount up to 50 g/L; (iv) hexoses in an amount up to 35 g/L; (v) furfural in an amount up to 1000 ppm; and (vi) less than 200 ppm calcium. In some examples, the broth additionally comprises: (vii) less than 1000 ppm acetic acid; and (viii) less than 1000 ppm formic acid. Optionally, the broth further comprises a C6-12 monoalcohol in an amount up to 100 ppm. In some examples, the broth additionally comprises a microorganism.

[0016] In one aspect, the disclosure provides a Xylitol composition. In one embodiment, the Xylitol composition comprises: (i) at least 98% Xylitol weight/weight relative to total dissolved solids; (ii) oligosaccharides in an amount of up to 1% weight/weight relative to total dissolved solids; and (iii) hexoses in an amount up to 1%. In some examples, the Xylitol composition additionally comprises ash in an amount of up to 0.25% weight/weight relative to total dissolved solids. Optionally, the Xylitol composition further comprises furfural in an amount up to 1000 ppm. Optionally, the Xylitol composition additionally comprises an amine in an amount of up to 100 ppm, and in which the amine comprises at least 12 carbon atoms. Optionally, the Xylitol composition further comprises a C6-12 monoalcohol in an amount up to 100 ppm. In some examples, the hexoses are selected from glucose, galactose, mannose, and fructose. Optionally, the Xylitol composition further comprises less than 100 ppm of arabitol, such as less than 1 ppm of arabitol. Optionally, the Xylitol composition further comprises less than 100 ppm of galactitol, such as less than 1 ppm of galactitol. Optionally, the composition is derived from a hydrolyzate of a lignocellulose-containing biomass. Optionally, the composition is crystalline. Optionally, the composition is provided as an aqueous solution. In some examples, the aqueous solution comprises at least 50% weight/weight dissolved solids.

[0017] In one aspect, the disclosure provides a method of producing a refined hemicellulose sugar stream suitable for conversion to Xylitol. In one embodiment, the method comprises: (i) extracting hemicellulose sugars from the biomass, thereby obtaining a hemicellulose sugar stream and a lignocellulose remnant stream; (ii) contacting the hemicellulose sugar stream with an amine extracting agent to form a mixture; (iii) separating from the mixture an organic stream comprising the amine extracting agent and at least one impurity and a refined hemicellulose sugar stream; and (iv) measure concentrations of at least one of xylose, arabinose, hexoses, disaccharides, ash, acetic acid, formic acid, phenolic compounds, furfural, calcium, and nitrogen; wherein the refined hemicellulose sugar stream is suitable for conversion to Xylitol if the refined stream comprises: (1) at least 50% xylose weight/weight relative to total dissolved sugars; (2) at least 10% weight/weight hexoses relative to total dissolved sugars; and (3) less than 200 ppm calcium; and wherein the refined stream suitable for conversion to Xylitol further comprises at least one feature selected from: (4) arabinose in an amount of up to 12% weight/weight relative to total dissolved sugars; (5) disaccharides in an amount of up to 8% weight/weight relative to total dissolved sugars; (6) ash in an amount up to 0.25% weight/weight; (7) less than 1000 ppm acetic acid; (8) less than 1000 ppm formic acid; (9) phenolic compounds in an amount up to 200 ppm; (10) furfural in an amount up to 200 ppm; and (11) nitrogen in an amount up to 1000 ppm; and in which the refined stream unsuitable for conversion to Xylitol is further refined.

[0018] In some examples, the refined stream suitable for conversion to Xylitol further comprises furfural in an amount up to 200 ppm. Optionally, the refined stream suitable for conversion to Xylitol further comprises arabinose in an amount of up to 12% weight/weight relative to the total dissolved sugars. Optionally, the refined stream suitable for conversion to Xylitol further comprises disaccharides in an amount of up to 8% weight/weight relative to the total dissolved sugars. Optionally, the refined stream suitable for conversion to Xylitol additionally comprises ash in an amount up to 0.25% weight/weight. Optionally, the refined stream suitable for conversion to Xylitol further comprises acetic acid in an amount up to 1000 ppm. Optionally, the refined stream suitable for conversion to Xylitol further comprises formic acid in an amount up to 1000 ppm. Optionally, the refined stream suitable for conversion to Xylitol further comprises phenolic compounds in an amount up to 200 ppm. Optionally, the refined stream suitable for conversion to Xylitol further comprises nitrogen in an amount up to 1000 ppm.

INCORPORATION BY REFERENCE

[0019] All publications, patents, and patent applications mentioned in this specification are hereby incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. PCT/IL2012/050118, filed on April 2, 2012, PCT/US2013/039585, filed on May 3, 2013, PCT/US2013/068824, filed on November 6, 2013, PCT/US2014/053956, filed on September 3, 2014, U.S. App. At the. 62/100,791, filed January 7, 2015, and U.S. App. At the. 62/249,801, filed November 2, 2015, are incorporated by reference.

BRIEF DESCRIPTION OF THE FIGURES

[0020] Fig. 1 illustrates a schematic diagram of exemplary conversion processes for converting biomass into downstream products, such as a refined hemicellulose sugar stream.

[0021] Fig. 2A illustrates a schematic diagram of exemplary conversion processes for converting a xylose-enriched hemi-cellulose sugar mixture to downstream products such as Xylitol, xylose, and furfural.

[0022] Fig. 2B illustrates a schematic diagram of an exemplary process for converting a refined hemicellulose sugar stream to Xylitol.

[0023] Fig. 2C illustrates a schematic diagram of exemplary processes for converting a xylose-stripped hemicellulose sugar mixture to downstream products such as arabinose and methane.

[0024] Fig. 3 illustrates a schematic diagram of exemplary conversion processes for purifying an acidic hemicellulose sugar stream.

[0025] Fig. 4 illustrates a schematic diagram of an exemplary conversion process for converting a hemicellulose sugar mixture into a solution comprising Xylitol, with optional refinement of the solution to crystalline or liquid Xylitol products.

[0026] Fig. 5 illustrates a schematic diagram of an exemplary conversion process for converting a hemicellulose sugar mixture to a solution comprising Xylitol, with optional refining of Xylitol to crystalline or liquid Xylitol products.

[0027] Fig. 6 illustrates the results of a pulse test schedule showing fractionation of a hemicellulose sugar blend to obtain xylose-enriched and xylose-stripped sugar blends.

[0028] Fig. 7 illustrates the results of a pulse test schedule showing fractionation of a mother liquor after Xylitol crystallization to obtain Xylitol-enriched and Xylitol-depleted sugar blends.

[0029] Fig. 8 illustrates a schematic diagram of exemplary sequential processes for washing biomass.

[0030] Fig. 9 illustrates a schematic diagram of exemplary sequential processes for washing and dehydration of lignocellulosic biomass after extraction of hemicellulose sugars.

[0031] Fig. 10 illustrates the residual ash content of washed bagasse samples.

DETAILED DESCRIPTION OF THE INVENTION

[0032] The present disclosure relates to processing and refining lignocellulosic biomass to produce hemicellulose sugars, and converting the same to high-value products (eg Xylitol). Conversion of the hemicellulose sugars to high value products can be accomplished by any suitable chemical, catalytic, enzymatic, metabolic, fermentation, or bioconversion process, or a combination thereof. Optionally, hemicellulose sugars are converted into high-value products by a fermentation process.

[0033] In one aspect, the disclosure provides a method of producing Xylitol from a lignocellulose-containing biomass. In one example, the method comprises: (i) extracting the hemicellulose sugars from the biomass, thereby obtaining a hemicellulose sugar stream and a lignocellulose remnant stream; (ii) contacting the hemicellulose sugar stream with an extracting agent (e.g., an amine extracting agent) to form a mixture; and (iii) separating from the mixture an organic stream comprising the extracting agent and at least one impurity, and a refined hemicellulose sugar stream. Optionally, the method further comprises: (iv) fermenting the refined hemicellulose sugar stream to produce a fermentation broth comprising Xylitol; and (v) recovering Xylitol from the fermentation broth. Optionally, the method further comprises reducing the ash content and soil content of the biomass prior to extracting hemicellulose sugars from the biomass.

[0034] In one aspect, the disclosure provides a method of producing Xylitol by fermenting a refined hemicellulose sugar stream derived from a lignocellulosic hydrolyzate. In one example, the method comprises converting xylose in the refined hemicellulose sugar stream to Xylitol through fermentation by a microorganism. Optionally, the hemicellulose sugar stream comprises: 50 to 90% xylose weight/weight relative to total dissolved sugars, less than 200 ppm calcium and furfural in an amount up to 1000 ppm.

[0035] In one aspect, the disclosure provides a method of producing a refined hemicellulose sugar stream suitable for conversion to Xylitol. In one example, the method comprises: (i) extracting hemicellulose sugars from the biomass, thereby obtaining a hemicellulose sugar stream and a lignocellulose remnant stream; (ii) contacting the hemicellulose sugar stream with an extracting agent (e.g., an amine extracting agent) to form a mixture; (iii) separating from the mixture an organic stream comprising the extracting agent and at least one impurity, and a refined hemicellulose sugar stream; and (iv) measuring concentrations of at least one of xylose, arabinose, hexoses, disaccharides, ash, acetic acid, formic acid, phenolic compounds, furfural, levulinic acid, calcium, and nitrogen; wherein a refined hemicellulose sugar stream is suitable for conversion to Xylitol if the refined stream comprises: (1) at least 50% xylose weight/weight relative to total dissolved sugars; (2) at least 10% weight/weight hexoses relative to total dissolved sugars; and (3) less than 200 ppm calcium; and wherein the refined stream suitable for conversion to Xylitol further comprises at least one feature selected from: (4) arabinose in an amount of up to 12% weight/weight relative to total dissolved sugars; (5) disaccharides in an amount of up to 8% weight/weight relative to total dissolved sugars; (6) ash in an amount up to 0.25% weight/weight; (7) acetic acid in amounts up to 1000 ppm; (8) formic acid in amounts up to 1000 ppm; (9) phenolic compounds in an amount up to 200 ppm; (10) furfural in an amount up to 200 ppm; and (11) nitrogen in an amount up to 1000 ppm; and in which the refined stream unsuitable for conversion to Xylitol is further refined.

[0036] A biomass embodied in an object method or system disclosed herein is typically high in xylan content. The biomass may be derived from wood, softwood, hardwood, such as alder, aspen, birch, beech, maple, poplar, eucalyptus, and willow, plants or plant constituents, grains, such as wheat, barley, rice, rye and oats, grain particulates such as straw, husks, chaff, fiber, and stalks, corn cobs, corn husks, corn fiber, nut hulls, almond husks, coconut husks, bagasse, seed bran cotton, and cottonseed hulls. When wood is used as a starting material, it is advantageously used as shavings or sawdust. Preferably, the biomass is selected from hardwood, such as birch and eucalyptus, bagasse, and sugar cane leaves, or a combination thereof.

[0037] A schematic of exemplary conversion processes for converting biomass into a refined hemicellulose sugar stream is provided in Fig. 1. Optionally, the lignocellulose-containing biomass is pre-treated (1770) prior to extraction of hemicellulose sugars. In some examples, pre-treatment of the biomass is not required, ie the lignocellulose-containing biomass can be used directly in the hemicellulose sugar extraction. A schematic diagram of current exemplary counter processes for biomass washing is provided in Fig. 8. The pre-treatment may comprise a reduction in the size of the biomass (eg mechanical breaking, milling, or grinding). Optionally, the lignocellulose-containing biomass is ground such that the average particle size of the resulting biomass is between about 100 to 1000 microns, such as about 400-5000 microns, about 100-400 microns, about 400-1000 microns. microns, about 1,000-3,000 microns, about 3,000-5,000 microns, or about 5,000-10,000 microns. The average particle size of crushed biomass can be less than 10,000 microns, less than 9,000 microns, less than 8,000 microns, less than 7,000 microns, less than 6,000 microns, less than 5,000 microns, less than 4,000 microns, less than 3000 microns, less than 2000 microns, less than 1000 microns, or less than 500 microns.

[0038] The pre-treatment of biomass containing lignocellulose can comprise the reduction of ash content and soil content of the biomass before the extraction of hemicellulose sugars from the biomass. In some examples, the lignocellulose-containing biomass comprising greater than about 4% weight/weight, greater than about 5% weight/weight, greater than about 6% weight/weight, greater than about 7% weight/weight, or greater than about 8% weight/weight of apparent ash (as measured by incineration of a dry sample of biomass in accordance with NREL/TP-510-42622) is devoid of soils and devoid of ash. Ash values greater than about 4% may be indicative of physical incorporation of soil particles into the biomass during a growing season, in which soil particles contact and are enclosed by the biomass as they grow. Reducing the ash and soil content of the biomass may comprise one or more stages of fluidising, washing and dewatering the biomass slurry. A method for reducing ash and soil content may comprise at least one and up to n stages of re-fluiding and grinding (e.g. grinding) of the biomass, and at least one and up to m stages of washing and dewatering of biomass, where n is 2, 3, 4, 5, 6, 7, 8, 9 or 10, and m is 2, 3, 4, 5, 6, 7, 8, 9 or 10. Optionally, n is equal to m. In some examples, m is greater than n, or n is greater than m. Two or more such shear and high pressure ash treatment cycles may be required to reduce the ash content of the biomass to less than 6%, less than 5%, less than 4%, or less than 3% weight/weight of ash.

[0039] Hemicellulose sugars can be extracted from lignocellulosic biomass by any suitable method (1700), for example using an aqueous acidic solution. The aqueous acid solution may comprise any acid, such as an inorganic acid or an organic acid. Preferably, the solution comprises an inorganic acid, such as H2SO4, H2SO3 (which may be introduced as dissolved acid or as SO2 gas), or HCl. In some examples, the aqueous acid solution may comprise an inorganic acid and/or an organic acid, including, for example, H2SO4, H2SO3, HCl, or acetic acid, or combinations thereof. The aqueous acid solution may contain an acid in an amount of about 0 to 2% acid, or more, such as about 0-1.0%, about 0-1.5%, about 0.5- 1.5%, about 0.5-2.0%, about 1.0-2.0%, about 1.5-2.0%, about 0.21.0%, about 0 .2-0.7%, about 0-0.2%, about 0.2-0.4%, about 0.4-0.6%, about 0.6-0.8%, about 0.8-1.0%, about 1.01.2%, about 1.2-1.4%, about 1.4-1.6%, about 1.6-1, 8%, or about 1.8-2.0% weight/weight. Optionally, the aqueous solution for the extraction includes 0.2 - 0.7% H2SO4 and 0 - 3000 ppm SO2. The pH of the aqueous acidic solution can range from about pH 1 to pH 5, such as about pH 1 to pH 3.5.

[0040] Elevated temperature or pressure can be used to extract hemicellulose sugars from biomass. In some examples, a temperature in the range of about 100 - 200 °C is used. A temperature greater than 50°C, greater than 60°C, greater than 70°C, greater than 80°C, greater than 90°C, greater than 100°C, greater than 110°C , greater than 120°C, greater than 130°C, greater than 140°C, greater than 150°C, greater than 160°C, greater than 170°C, greater than 180°C, greater than 190°C, or greater than 200°C, can be used in extraction. Preferably, the temperature is in the range of 90-170°C, such as 100-165°C, 110-160°C, 120-150°C, 130-155°C or 140-150°C. The pressure can be in the range of about 0.4 - 10 mPa, such as 0.4 - 5 mPa. Optionally, the pressure is less than 20 mPa, such as less than 10 mPa, less than 9 mPa, less than 8 mPa, less than 7 mPa, less than 6 mPa, or less than 5 mPa. In some examples, the extraction mixture is heated for 0.1 - 5 hours, preferably 0.1 - 3 hours, 0.1 - 1 hour, 0.5 - 1.5 hours, 0.5 - 2 hours , 1-2 hours, or 2-3 hours. The extraction process can have a cool down period of less than an hour. Optionally, hemicellulose sugars are extracted from biomass by contacting the biomass with an aqueous acidic solution and heating the resulting mixture to a temperature of more than 50°C at a pressure of less than 10 mPa.

[0041] Hemicellulose sugar extraction can produce, in a single extraction process, a hemicellulose sugar stream (1700-A) containing at least 75% monomeric sugars, such as more than 80%, more than 85%, more than 90%, more than 91%, more than 92%, more than 93%, more than 94%, more than 95%, more than 96%, more than 97%, more than 98%, or more than 99% monomeric sugars. The hemicellulose sugar stream can contain 80-99% monomer sugars. In some examples, at least about 70%, at least 75%, at least 80%, at least 85%, at least 90%, or even at least 95% or more of the hemicellulose sugars present in the biomass can be extracted using a method of disclosure. Hemicellulose sugar extraction can produce minute amounts of lignocellulose degradation products, such as furfural, hydroxymethyl furfural, levulinic acid, and formic acid. A xylose yield of greater than 70%, optionally greater than 80%, of theoretical value can be achieved.

[0042] The extraction of hemicellulose sugars from the biomass results in a remnant stream of lignocellulose (1700-P1) comprising lignin and cellulose. A schematic diagram of exemplary sequential processes for washing and dehydrating a remaining stream of lignocellulose after extraction of hemicellulose sugars is provided in Fig. 9. In some examples, extraction of hemicellulose sugars does not remove a substantial amount of cellulosic sugars. For example, extracting sugars from hemicellulose does not remove more than 1%, more than 2%, more than 5%, more than 10%, more than 15%, more than 20%, more than 30%, more than 40%, more than 50%, or more than 60% weight/weight pulp. In some examples, the remaining lignocellulose stream comprises less than 50%, less than 45%, less than 40%, less than 35%, less than 30%, less than 25%, less than 20 %, less than 15%, less than 10%, less than 5%, less than 2%, or less than 1% weight/weight hemicellulose. The remaining lignocellulose stream may comprise less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, less than 2%, or less than 1% w/w ash. In some examples, the remaining lignocellulose stream comprises 0.001-5% weight/weight ash, such as 0.01-4%, 0.1-3%, 0.1-2%, or 0.1-1% weight/weight of ash. In some examples, the remaining stream of lignocellulose comprises lignin, cellulose, hemicellulose in an amount less than 5% weight/weight, and ash in an amount less than 4% weight/weight. In some examples, less than 10%, less than 5%, less than 4%, less than 3%, less than 2.5%, less than 2%, less than 1.5%, or less than 1% of the lignocellulose solids remain in the hemicellulose sugar stream. Optionally, the remaining lignocellulose stream comprises less than 75%, less than 65%, less than 55%, less than 45%, less than 35%, less than 25%, less than 15 %, or less than 10% weight/weight water. The remaining lignocellulose stream may comprise greater than 20%, greater than 30%, greater than 40%, greater than 50%, greater than 60%, greater than 70%, or greater than 80% weight / weight of solids. The remaining lignocellulose stream may comprise less than 10%, less than 7.5%, less than 5%, less than 4%, less than 3%, less than 2%, less than 1% , or less than 0.5% weight/weight residual soluble carbohydrate. In some examples, the remaining lignocellulose stream comprises about 0.01-5% weight/weight soluble carbohydrate, such as 0.1-5%, 0.5-5%, 0.5-2.5 %, or 0.1-2.5% weight/weight soluble carbohydrates. The remaining lignocellulose stream may comprise less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, less than 0.5%, less than 0, 2%, or less than 0.1% weight/weight sulfate. In some examples, the remaining stream of lignocellulose comprises 0.001-3% wt/wt sulfate, such as 0.01-3%, 0.01-2%, 0.01-1%, or 0.001-1% wt/wt. sulfate weight. The remaining lignocellulose stream may comprise soluble carbohydrates in a total solids amount of less than 5%, ash in a total solids amount of less than 4%, and sulfate in a total solids amount of less than 4%. less than 3%.

[0043] Impurities, such as ash, acid soluble lignin, furfural, fatty acids, organic acids, such as acetic acid and formic acid, methanol, proteins and/or amino acids, glycerol, sterols, fatty acids, resin acid or Waxy materials, or combinations thereof, can be extracted along with the hemicellulose sugars under the same conditions in the hemicellulose sugar stream. At least some of these impurities can be separated from the hemicellulose sugar stream by solvent extraction (eg using an amine extracting agent).

[0044] The hemicellulose sugar stream can be refined and optionally fractionated according to the processes disclosed in PCT/US2013/039585, incorporated herein by reference. The hemicellulose sugar stream can optionally be filtered, centrifuged, or concentrated by evaporation. Optionally, the hemicellulose sugar stream is contacted with a strong acid cation exchanger (eg, in H+ form) to convert salts to the respective acids. In some examples, the hemicellulose sugar stream is first contacted with a strong cation exchange resin and then contacted with an amine extracting agent.

[0045] Optionally, impurities are removed from the hemicellulose sugar stream by contacting the stream with an amine extracting agent to form a mixture, in which the mixture may comprise an organic stream and an aqueous stream (1710). Exemplary conversion processes for purifying the hemicellulose sugar stream (1700-A and 1800-A) are depicted in Fig. 3, including amine extraction 1831. In some examples, the organic stream (1831-A) comprises the amine extraction agent and at least one impurity. Optionally, the at least one impurity is selected from a mineral acid (eg, H2SO4, H2SO3, and HCl), an organic acid (eg, acetic acid and formic acid), furfural, hydroxymethylfurfural, and acid soluble lignin. The aqueous stream may comprise hemicellulose sugars. After separating the organic stream, the aqueous stream is referred to herein as a refined hemicellulose sugar stream (1710-P1 and 1831-B).

[0046] The amine extracting agent may comprise 1090%, such as 10-80%, 10-70%, 10-60%, 10-50%, 10-40%, 20-80%, 20-70% , 20-60%, 20-50%, 20-40%, 15-80%, 15-70%, 15-60%, 1550%, 15-40%, 15-35%, 25-80%, 25 -70%, 25-60%, 25-50%, 25-40%, or 25-35% weight/weight of one or more amines having at least 20 carbon atoms. Such amine(s) may be primary, secondary, or tertiary amines. Examples of tertiary amines include trilaurylamine (TLA; for example, COGNIS ALAMINE 304 from Cognis Corporation; Tucson AZ; USA), trioctylamine, triisooctylamine, tricaprylylamine, and tridecylamine.

[0047] The amine extracting agent may additionally comprise a diluent. In some examples, the amine extracting agent comprises at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80% , or at least 90% weight/weight, such as 55-85% weight/weight, of a diluent. Optionally, the diluent is an alcohol, such as butanol, isobutanol, pentanol, hexanol, octanol, decanol, dodecanol, tetradecanol, pentadecanol, hexadecanol, octadecanol, eicosanol, docosanol, tetracosanol, and triacontanol. Optionally, the diluent is a long-chain alcohol (eg C6, C8, C10, C12, C14, C16 alcohol), or kerosene. In some examples, the diluent is n-hexanol or 2-ethyl-1-hexanol. Optionally, the diluent is 2-ethyl-1-hexanol. In some examples, the diluent comprises one or more additional components, such as a ketone, an aldehyde having at least 5 carbon atoms, or another alcohol.

[0048] Optionally, the amine extracting agent comprises an amine having at least 20 carbon atoms and a diluent (for example, an alcohol), such as a tertiary amine having at least 20 carbon atoms and an alcohol. In some examples, the amine extracting agent comprises a tertiary amine having from 20 to 50 carbon atoms and a diluent, wherein the diluent is a C6-12 monoalcohol. In some examples, the amine extracting agent comprises an amine having from 24-40 carbon atoms (e.g., trilaurylamine, trioctylamine, tricaprylylamine, or tridecylamine) and a diluent, in which the diluent is a C6-12 monoalcohol (e.g. example, hexanol, octanol, or 2-ethylhexanol). In some examples, the amine is trilaurylamine and the diluent is hexanol or 2-ethylhexanol.

[0049] The amine extracting agent may comprise an amine and a diluent in a ratio between 1:10 and 10:1 weight/weight, such as 1:9, 1:4, 3:7, 2:3, 1 :1, 3:2, 7:3, 4:1, or 9:1 weight/weight. Optionally, the amine extracting agent comprises trilaurylamine and a C6-12 monoalcohol in a ratio of 1:7, 2:7, 3:7, 6:4, 5.5:4.55, 4:7, 5: 7, 6:7, 7:7, 5:4, 3:4, 2:4, or 1:4 weight/weight. Optionally, the amine extracting agent comprises trilaurylamine and a C6-12 monoalcohol in about a 3:7 weight/weight ratio, such as a 3:7 weight/weight ratio of trilaurylamine and hexanol.

[0050] Optionally, the hemicellulose sugar stream is extracted with a currently counter amine extracting agent, for example, the hemicellulose sugar stream flows in an opposite direction to the flow of the amine extracting agent. The amine extraction can be conducted at any temperature at which the amine is soluble, such as 50-70°C. Optionally, the amine extraction comprises more than one extraction step (e.g., 2, 3, or 4 steps). The ratio of the amine extractor stream (organic stream) to the hemicellulose sugar stream (aqueous stream) can range from about 0.5:1 to about 5:1 weight/weight, such as about 0. ,5:1, about 1:1, about 1.5:1, about 2:1, about 2.5:1, about 3:1, about 3.5:1, about 4:1 , about 4.5:1, or about 5:1. In some examples, the ratio of organic stream to aqueous stream is about 1.5-3.0:1 weight/weight.

[0051] After contacting the hemicellulose sugar stream with the amine extracting agent, the resulting mixture can be separated into an organic stream (i.e. the organic phase) comprising the amine extracting agent and at least one impurity and a stream of refined hemicellulose sugar (i.e. the aqueous phase). At least a portion of organic acids or inorganic acids (eg, the acids used in the extraction of hemicellulose sugar), and other impurities, may be extracted in the organic stream. In some examples, the organic stream is counted with an aqueous stream in a counter current mode to recover any residual sugars absorbed into the organic stream. The organic stream may comprise less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, less than 0.8%, less than 0.6% , less than 0.5%, less than 0.4%, less than 0.3%, less than 0.2%, or less than 0.1% weight/weight of hemicellulose sugars, such as 0.01% to 4% hemicellulose sugars. In some examples, the refined hemicellulose sugar stream comprises less than 3%, less than 2%, less than 1%, less than 0.8%, less than 0.6%, less than than 0.5%, less than 0.4%, less than 0.3%, less than 0.2%, or less than 0.1% weight/weight acid, such as 0.01% to 3% acid. In some examples, the refined hemicellulose sugar stream comprises less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, less than 0.8 %, less than 0.6%, less than 0.5%, less than 0.4%, less than 0.3%, less than 0.2%, or less than 0.1% weight/weight of an amine having at least 20 carbon atoms, such as 0.01% to 4% of an amine. In some examples, the refined hemicellulose sugar stream comprises less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, less than 0.8%, less than 0.6%, less than 0.5%, less than 0.4%, less than 0.3%, less than 0.2%, or less than 0.1% weight/ weight of an impurity, such as 0.1% to 4% of an impurity, in which the impurity is selected from ash, acid soluble lignin, furfural, fatty acids, organic acids, such as acetic acid and formic acid, mineral acids, such as hydrochloric acid and sulfuric acid, furfural, hydroxymethylfurfural, methanol, proteins, amino acids, glycerol, sterols, resin acid, and waxy materials. The refined hemicellulose sugar stream may comprise less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, less than 0.8%, less than 0.6%, less than 0.5%, less than 0.4%, less than 0.3%, less than 0.2%, or less than 0.1% weight/weight furfural , such as 0.1% to 4% furfural. In some examples, the refined hemicellulose sugar stream comprises less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, less than 0.8%, less than 0.6%, less than 0.5%, less than 0.4%, less than 0.3%, less than 0.2%, or less than 0.1% weight/ ash weight, such as 0.1% to 4% ash.

[0052] The refined hemicellulose sugar stream can be further purified. For example, residual diluent in the refined hemicellulose sugar stream can be removed using a packed distillation column. Distillation can remove at least 70%, at least 80%, at least 90%, or at least 95% of residual diluent in the refined hemicellulose sugar stream. In some examples, the refined hemicellulose sugar stream is contacted with a strong acid cation exchanger (SAC) (1833) to remove residual diluent cations and residual amines, then optionally contacted with a weak base anion exchanger (WBA) (1834) to remove excess protons. Optionally, the refined hemicellulose sugar stream is purified using a distillation column (eg, a packed distillation column), followed by a strong acid cation exchanger. In some examples, the refined hemicellulose sugar stream is contacted with a weak base anion exchanger (WBA) to remove excess protons. The refined hemicellulose sugar stream can be pH adjusted, optionally after contacting the stream with a SAC exchanger and/or WBA exchanger. The refined hemicellulose sugar stream can be distilled or evaporated, then further polished by contacting with a SAC resin, a WBA resin, and an MB resin, and optionally concentrated by evaporation. In some examples, the refined hemicellulose sugar stream is evaporated (1835) to 20-80% weight/weight of dissolved sugars, such as 25-65% or 30-40% weight/weight of dissolved sugars, thereby forming , a concentrated sugar solution (1836). Evaporation can be conducted in any conventional evaporator, for example a multiple effect evaporator, or a mechanical vapor recompression (MVR) evaporator.

[0053] The residual solvent present in the hemicellulose sugar stream or concentrated sugar solution can also be removed by evaporation. For example, a solvent that forms a heterogeneous azeotrope with water can be separated and optionally returned to the solvent cycle. Optionally, the refined hemicellulose sugar stream can be contacted with activated carbon to remove residual organic impurities. The refined hemicellulose sugar stream can also be contacted with the mixed bed resin system to remove any residual ions or color bodies.

[0054] The refined hemicellulose sugar stream produced by the subject systems and methods may comprise sugars in a highly suitable proportion as a feed for fermentation, such as for the production of Xylitol.

[0055] In some examples, the refined hemicellulose sugar stream comprises at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70 %, at least 75%, at least 80%, at least 85%, at least 90%, or at least 95% weight/weight of xylose relative to total dissolved sugars. Optionally, the refined hemicellulose sugar stream comprises between 40% and 95% weight/weight xylose relative to total dissolved sugars, such as 50% to 85% xylose.

[0056] In some examples, the refined hemicellulose sugar stream comprises less than 15%, less than 14%, less than 13%, less than 12%, less than 11%, less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, or less than 2 % weight/weight of arabinose relative to total dissolved sugars. Optionally, the refined hemicellulose sugar stream comprises between 1% and 15% weight/weight arabinose relative to the total dissolved sugars, such as 3% to 12% arabinose.

[0057] In some examples, the refined hemicellulose sugar stream comprises at least 5%, at least 10%, at least 12%, at least 15%, at least 17%, at least 20%, at least 22 %, at least 25%, at least 27%, at least 30%, at least 32%, at least 35%, at least 37%, at least 40%, at least 42%, at least 45%, at least 50 %, at least 52%, at least 55%, or at least 57% weight/weight of hexoses relative to total dissolved sugars. Optionally, the refined hemicellulose sugar stream comprises between 5% and 60% weight/weight of hexoses relative to the total dissolved sugars, such as 10% to 45% of hexoses.

[0058] In some examples, the hexoses comprise glucose, galactose, mannose and fructose, in which the glucose and fructose optionally comprise at least 30%, at least 40%, at least 45%, at least 50%, at least 55% , at least 60%, at least 65%, at least 70%, at least 75%, or at least 80% weight/weight of the hexoses. Optionally, the refined hemicellulose sugar stream comprises between 30% and 85% weight/weight glucose and fructose relative to the hexoses, such as 50% to 80% glucose and fructose.

[0059] In some examples, the refined hemicellulose sugar stream comprises at least 5%, at least 10%, at least 12%, at least 15%, at least 17%, at least 20%, at least 22 %, at least 25%, at least 27%, at least 30%, at least 32%, at least 35%, at least 37%, at least 40%, at least 42%, at least 45%, at least 50 %, at least 52%, at least 55%, or at least 57% weight/weight glucose relative to total dissolved sugars. Optionally, the refined hemicellulose sugar stream comprises between 5% and 60% weight/weight glucose relative to total dissolved sugars, such as 10% to 45% glucose.

[0060] In some examples, the refined hemicellulose sugar stream comprises xylose in a hexose ratio of at least 1:1 weight/weight, such as at least 1.5:1, at least 2:1, at least at least 3:1, at least 4:1, at least 5:1, at least 6:1, or at least 7:1 weight/weight. Optionally, the ratio of xylose to hexoses in the refined hemicellulose sugar stream is between 1:1 and 8:1 weight/weight, such as between 1.5:1 and 5:1 weight/weight.

[0061] In some examples, the refined hemicellulose sugar stream comprises less than 15%, less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, less than 2%, or less than 1% weight/weight of disaccharides relative to total dissolved sugars. Optionally, the refined hemicellulose sugar stream comprises between 0.1% and 15% weight/weight of disaccharides relative to total dissolved sugars, such as 0.5% to 8% of disaccharides.

[0062] In some examples, the refined hemicellulose sugar stream comprises less than 16%, less than 14%, less than 12%, less than 10%, less than 8%, less than 6%, less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, or less than 0.5% weight/weight of oligosaccharides relative to total dissolved sugars, wherein said oligosaccharides comprise at least 3 monosaccharide units. Optionally, the refined hemicellulose sugar stream comprises between 0.1% and 10% weight/weight oligosaccharides relative to total dissolved sugars, such as 0.5% to 5% oligosaccharides.

[0063] In some examples, the refined hemicellulose sugar stream comprises ash in an amount of up to 2%, up to 1.5%, up to 1%, up to 0.75%, up to 0.50%, up to 0, 25%, up to 0.1%, or up to 0.05% weight/weight ash. Optionally, the refined hemicellulose sugar stream comprises between 0.001% and 1% weight/weight ash, such as 0.001% to 0.25% ash.

[0064] In some examples, the ash comprises Ca, Cu, Fe, K, Mg, Mn, Na, P, S, or Si, or a combination thereof. In some examples, the refined hemicellulose sugar stream comprises Ca, Cu, Fe, K, Mg, Mn, Na, P, S, and Si at less than 1000 ppm, less than 750 ppm, less than 500 ppm , less than 400 ppm, less than 300 ppm, less than 200 ppm, less than 100 ppm, less than 50 ppm, or less than 10 ppm each. Optionally, the refined hemicellulose sugar stream comprises between 1 ppm and 1000 ppm each of Ca, Cu, Fe, K, Mg, Mn, Na, P, S, and Si, such as 1 ppm to 250 ppm each of Ca, Cu, Fe, K, Mg, Mn, Na, P, S, and Si. In some examples, the refined hemicellulose sugar stream comprises less than 1000 ppm, less than 750 ppm, less than 500 ppm, less than 400 ppm, less than 300 ppm, less than 200 ppm, less than than 100 ppm, less than 50 ppm, or less than 10 ppm of calcium. Optionally, the refined hemicellulose sugar stream comprises between 1 ppm and 1000 ppm calcium, such as 1 ppm to 250 ppm calcium.

[0065] In some examples, the refined hemicellulose sugar stream comprises phenolic compounds in amounts up to 1000 ppm, up to 750 ppm, up to 500 ppm, up to 400 ppm, up to 300 ppm, up to 200 ppm, up to 100 ppm, up to 50 ppm, or even 10 ppm. Optionally, the refined hemicellulose sugar stream comprises between 1 ppm and 1000 ppm of phenolic compounds, such as 1 ppm to 250 ppm of phenolic compounds.

[0066] In some examples, the refined hemicellulose sugar stream comprises furfural in an amount of up to 1000 ppm, up to 750 ppm, up to 500 ppm, up to 400 ppm, up to 300 ppm, up to 200 ppm, up to 100 ppm, up to 50 ppm, or even 10 ppm. Optionally, the refined hemicellulose sugar stream comprises between 1 ppm and 1000 ppm furfural, such as 1 ppm to 250 ppm furfural.

[0067] In some examples, the refined hemicellulose sugar stream comprises less than 1000 ppm, less than 750 ppm, less than 500 ppm, less than 400 ppm, less than 300 ppm, less than 200 ppm, less than 100 ppm, less than 50 ppm, or less than 10 ppm of organic acids, such as acetic acid, levulinic acid, formic acid, and lactic acid. Optionally, the refined hemicellulose sugar stream comprises between 1 ppm and 1000 ppm of organic acids, such as 1 ppm to 250 ppm of organic acids. Optionally, the refined hemicellulose sugar stream comprises between 1 ppm and 1000 ppm acetic acid, such as 1 ppm to 250 ppm acetic acid. Optionally, the refined hemicellulose sugar stream comprises between 1 ppm and 1000 ppm formic acid, such as 1 ppm to 250 ppm formic acid.

[0068] In some examples, the refined hemicellulose sugar stream comprises an amine in an amount of up to 1000 ppm, up to 750 ppm, up to 500 ppm, up to 400 ppm, up to 300 ppm, up to 200 ppm, up to 100 ppm, up to 50 ppm, or up to 10 ppm, and in which the amine comprises at least 12 carbon atoms. Optionally, the amine is a laurylamine, such as monolaurylamine, dilaurylamine, or trilaurylamine. Optionally, the refined hemicellulose sugar stream comprises between 0.1 ppm and 1000 ppm of an amine comprising at least 12 carbon atoms, such as 0.1 ppm to 250 ppm of an amine comprising at least 12 carbon atoms.

[0069] In some examples, the refined hemicellulose sugar stream comprises an alcohol in an amount of up to 1000 ppm, up to 750 ppm, up to 500 ppm, up to 400 ppm, up to 300 ppm, up to 200 ppm, up to 100 ppm, up to 50 ppm, or up to 10 ppm. The alcohol can be any alcohol that can be used herein as a diluent, such as butanol, pentanol, hexanol, or 2-ethyl-1-hexanol. In some examples, the alcohol is a C6-1 monoalcohol, optionally present in the refined hemicellulose sugar stream in an amount up to 200 ppm. Optionally, the refined hemicellulose sugar stream comprises between 1 ppm and 1000 ppm of said alcohol, such as 1 ppm to 250 ppm of said alcohol.

[0070] In some examples, the refined hemicellulose sugar stream comprises nitrogen in an amount up to 1000 ppm, up to 750 ppm, up to 500 ppm, up to 400 ppm, up to 300 ppm, up to 200 ppm, or up to 150 ppm. Optionally, the refined hemicellulose sugar stream comprises between 1 ppm and 1000 ppm nitrogen, such as 1 ppm to 250 ppm nitrogen. Nitrogen can be total Kjeldahl nitrogen measured using the Kjeldahl method.

[0071] In some examples, the refined hemicellulose sugar stream comprises: at least 50% weight/weight xylose; arabinose in an amount up to 12% weight/weight; at least 10% wt/wt hexoses; disaccharides in an amount up to 8% weight/weight; ash in an amount up to 0.25% weight/weight; furfural in an amount up to 200 ppm; and nitrogen in an amount up to 1000 ppm. In some examples, the refined hemicellulose sugar stream comprises: at least 50% weight/weight xylose; between 3% and 12% weight/weight of arabinose; at least 10% weight/weight hexoses; between 0.001% and 0.25% weight/weight of ash; between 1 ppm and 200 ppm of furfural; and between 1 ppm and 1000 ppm of nitrogen. Optionally, the refined hemicellulose sugar stream comprises 6575% xylose, 3-10% arabinose and 15-25% hexoses (all weight/weight relative to total dissolved sugars). The refined hemicellulose sugar stream may contain at least 90% weight/weight saccharides to total dissolved solids, such as at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least at least 96%, at least 97%, at least 98%, at least 99%, or at least 99.5% saccharides.

[0072] The refined hemicellulose sugar stream can have a high purity with respect to ash elements, organic acids, lignin derivatives and sugar degradation products. The refined hemicellulose sugar stream can comprise ash at a concentration of up to 1%, up to 0.5%, up to 0.1%, up to 0.05%, or up to 0.01% weight/weight relative to the total dissolved sugars , in which the ash comprises up to 500 ppm, up to 250 ppm, or up to 100 ppm of metal cations, and less than 100 ppm, less than 50 ppm, less than 30 ppm, or less than 20 ppm relative sulfur to total dissolved sugars. In some examples, a refined hemicellulose sugar stream is particularly suitable for fermentation processes that are sensitive to ash elements, or sulfur compounds. The refined hemicellulose sugar stream may comprise less than 5000 ppm of ash in total weight/weight relative to xylose, in which ash comprises selected elements of Na, Ca, Cu, Fe, K, Mg, Mn, S and P .

[0073] In some examples, the refined hemicellulose sugar stream comprises at least one characteristic selected from: (i) a ratio of disaccharides to total dissolved sugars of not more than 0.10 weight/weight; (ii) a ratio of xylose to total dissolved sugars of at least 0.70 weight/weight; (iii) a ratio of arabinose to total dissolved sugars of not more than 0.06 weight/weight; (iv) a ratio of galactose to total dissolved sugars of not more than 0.05 weight/weight; (v) a ratio of the sum of glucose and fructose to total dissolved sugars of not more than 0.15 weight/weight; (vi) a ratio of mannose to total dissolved sugars of not more than 0.05 weight/weight; (vii) a ratio of fructose to total dissolved sugars of not more than 0.10 weight/weight; (viii) phenolic compounds in an amount of not more than 1000 ppm; (ix) hexanol in an amount of not more than 0.1% weight/weight; (x) furfural in an amount of not more than 1000 ppm; (xi) organic acids in an amount of not more than 1000 ppm; and (xii) less than 1000 ppm each of the elements Ca, Cu, Fe, K, Mg, Mn, S and P relative to total dissolved sugars.

[0074] In some examples, the refined hemicellulose sugar stream comprises low levels of monosaccharides and additional disaccharides. Optionally, additional monosaccharides are selected from lyxose, xylulose, and ribulose. Optionally, additional disaccharides are selected from gentiobiose, sophorose, nigerose, laminaribiose, and kojibiose. These additional monosaccharides and disaccharides can be beneficial to fermentation processes. In some instances, such rare saccharides are biologically active and may act as promoters to increase enzyme expression activity or operate as cofactors to increase enzyme activity, thereby resulting in accelerated biological conversion.

[0075] Surprisingly, the refined hemicellulose sugar stream is particularly advantageous in a fermentation process capable of hydrogenating xylose to Xylitol, as the fermentation species can utilize the hexoses as its energy source, thus in some examples , eliminating the need to further purify or fractionate the sugar stream prior to the hydrogenation step. Additional purification steps commonly used to enrich the xylose content of a sugar stream, such as chromatographic separation or crystallization, may not be necessary prior to fermentation. In certain instances, the proportions of sugars in the refined hemicellulose sugar stream are ideal for fermentation to Xylitol, in which enrichment of the xylose concentration can reduce the efficiency and yield of the fermentation process. It is further understood that the high purity of the refined hemicellulose sugar stream is advantageous as a fermentation feed, as the concentrations of impurities known as possible fermentation inhibitors, such as phenols, furfurals, organic acids, and alcohols, are low.

[0076] A fermentation feedstock comprising the refined hemicellulose sugar stream can be utilized by a microorganism for producing a conversion product. In some examples, the conversion product is a reduced sugar, such as a sugar alcohol. Optionally, the sugar alcohol can be a sugar substitute, such as Xylitol. A schematic diagram of an exemplary process for converting a refined hemicellulose sugar stream to Xylitol is provided in Fig 2B. In some examples, a microorganism converts xylose in the refined hemicellulose sugar stream (1710-P1) to Xylitol (1950-P1). A method of the present disclosure may comprise fermentation (1900) of a fermentation raw material comprising the refined hemicellulose sugar stream to produce a fermentation broth comprising Xylitol. A schematic diagram of an exemplary conversion process for converting a hemicellulose sugar mixture to a solution comprising Xylitol, with optional refinement of the solution to crystalline (1960-A) or liquid (1950-A) Xylitol products, is provided in Fig. . 4 and Fig. 5.

[0077] The fermentation feedstock can have a composition very similar to the refined hemicellulose sugar stream. Optionally, additives are introduced into the refined hemicellulose sugar stream to generate the fermentation feedstock. Additives can be selected from nutrients, salts such as NaCl, MgSO4, and K2PO4, and yeast extract. As such, measured ash levels may be higher in the fermentation feedstock as compared to the refined hemicellulose sugar stream. Optionally, hexoses are added to the refined hemicellulose sugar stream to adjust the xylose:hexose ratio as required for a particular microorganism. In some examples, the concentration of hemicellulose sugars is adjusted in the fermentation feedstock by dilution (eg dilution with water), or concentration (eg evaporation).

[0078] The fermentation raw material may comprise at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75% , at least 80%, at least 90%, or at least 95% weight/weight of xylose relative to total dissolved sugars. Optionally, the fermentation feedstock comprises between 40% and 95% weight/weight xylose relative to total dissolved sugars, such as 50% to 90% xylose. In some examples, the fermentation feedstock additionally comprises at least 5%, at least 10%, at least 12%, at least 15%, at least 17%, at least 20%, at least 22%, at least at least 25%, at least 27%, at least 30%, at least 32%, at least 35%, at least 37%, at least 40%, at least 42%, at least 45%, at least 50%, at least at least 52%, at least 55%, or at least 57% weight/weight of hexoses relative to total dissolved sugars. Optionally, the fermentation raw material comprises between 5% and 60% weight/weight of hexoses relative to the total dissolved sugars, such as 10% to 45% of hexoses. In some examples, the fermentation feedstock further comprises less than 15%, less than 14%, less than 13%, less than 12%, less than 11%, less than 10%, less than than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, or less than 2% weight/weight of arabinose relative to total dissolved sugars. Optionally, the fermentation raw material comprises between 1% and 15% weight/weight arabinose relative to total dissolved sugars, such as 3% to 12% arabinose. In some examples, the fermentation feedstock further comprises less than 15%, less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than than 5%, less than 4%, less than 3%, less than 2%, or less than 1% weight/weight of disaccharides relative to total dissolved sugars. Optionally, the fermentation feedstock comprises between 0.1% and 15% weight/weight of disaccharides relative to total dissolved sugars, such as 0.5% to 8% disaccharides. In some examples, the fermentation feedstock further comprises less than 1000 ppm, less than 750 ppm, less than 500 ppm, less than 400 ppm, less than 300 ppm, less than 200 ppm, less than than 100 ppm, less than 50 ppm, or less than 10 ppm calcium. Optionally, the fermentation feedstock comprises between 1 ppm and 1000 ppm of calcium, such as 1 ppm to 250 ppm of calcium. In some examples, the fermentation feedstock further comprises furfural in an amount of up to 1000 ppm, up to 750 ppm, up to 500 ppm, up to 400 ppm, up to 300 ppm, up to 200 ppm, up to 100 ppm, up to 50 ppm, or up to 10 ppm. Optionally, the fermentation feedstock comprises between 1 ppm and 1000 ppm furfural, such as 1 ppm to 250 ppm furfural. In some examples, the fermentation feedstock further comprises less than 1000 ppm, less than 750 ppm, less than 500 ppm, less than 400 ppm, less than 300 ppm, less than 200 ppm, less than than 100 ppm, less than 50 ppm, or less than 10 ppm of organic acids, such as acetic acid, levulinic acid, formic acid, and lactic acid. Optionally, the fermentation feedstock comprises between 1 ppm and 1000 ppm of organic acids, such as 1 ppm to 1000 ppm of acetic acid. Optionally, the fermentation feedstock comprises between 1 ppm and 1000 ppm formic acid. In some examples, the fermentation feedstock further comprises an amine in an amount of up to 1000 ppm, up to 750 ppm, up to 500 ppm, up to 400 ppm, up to 300 ppm, up to 200 ppm, up to 100 ppm, up to 50 ppm, or up to 10 ppm, and in which the amine comprises at least 12 carbon atoms. Optionally, the amine is a laurylamine, such as monolaurylamine, dilaurylamine, or trilaurylamine. Optionally, the fermentation feedstock comprises between 0.1 ppm and 1000 ppm of an amine comprising at least 12 carbon atoms, such as 0.1 ppm to 250 ppm of an amine comprising at least 12 carbon atoms. In some examples, the fermentation feedstock further comprises a C6-12 monoalcohol in an amount of up to 1000 ppm, up to 750 ppm, up to 500 ppm, up to 400 ppm, up to 300 ppm, up to 200 ppm, up to 100 ppm, up to 50 ppm, or up to 10 ppm. Optionally, the fermentation feedstock comprises between 1 ppm and 1000 ppm of said C6-12 monoalcohol, such as 1 ppm to 250 ppm of said C6-12 monoalcohol. In some examples, the fermentation feedstock further comprises nitrogen in an amount of up to 1000 ppm, up to 750 ppm, up to 500 ppm, up to 400 ppm, up to 300 ppm, up to 200 ppm, or up to 150 ppm. Optionally, the fermentation feedstock comprises between 1 ppm and 1000 ppm of nitrogen, such as 1 ppm to 250 ppm of nitrogen. In some examples, the fermentation feedstock comprises: 50% to 90% weight/weight xylose; 10% to 45% weight/weight hexoses; arabinose in an amount up to 12% weight/weight; disaccharides in an amount up to 8% weight/weight; furfural in an amount up to 1000 ppm; and less than 200 ppm of calcium. In some examples, the fermentation feedstock further comprises less than 1000 ppm acetic acid, and less than 1000 ppm formic acid. Optionally, the fermentation feedstock further comprises a C6-12 monoalcohol in an amount of up to 100 ppm.

[0079] Several microorganisms have been developed to produce Xylitol through a fermentation process. Surprisingly, the refined hemicellulose sugar streams of the present disclosure are particularly well tolerated by many such microorganisms, and are efficiently converted to Xylitol without the need for additional purification, fractionation, separation, or crystallization processes prior to fermentation. Microorganism species capable of converting xylose in the refined hemicellulose sugar stream to Xylitol include yeasts, such as Pichia, Candida, Hansenula and Kluyveromyces. A strain of Candida tropicalis ATCC 13803 can be used to convert xylose to Xylitol using glucose in the refined hemicellulose sugar stream for cell growth (see, for example, US 5998181 and US 5686277). Xylitol can be produced by Candida guilliermondii FTI 20037 (see, for example, Mussatto and Roberto (2003) J. Appl. Microbiol. 95:331-337 ). Saccharomyces cerevisiae can be used to produce Xylitol (see, for example, US 5866382). A variety of fermentation systems are capable of converting a refined hemicellulose sugar stream to a high Xylitol, low arabitol product through the use of various strains of E. Coli (see, for example, PCT/US2011/021277, PCT /US2011/044696, and US Pub. No. 2013/0217070). These systems can utilize C6 sugars and some of the arabinose from a refined hemicellulose sugar stream as an energy source for proliferation and metabolism, while predominantly converting xylose to Xylitol with minimal co-conversion of arabinose to arabitol. Optionally, the microorganism is a microorganism described in US Pub. At the. 2013/0217070, such as HZ 1434, ZUC220, ZUC170, ZUC136, HZ 2061, or HZ 2062. A two-substrate fermentation with C. tropicalis and Candida Parapsilosis using glucose for cell growth and xylose for Xylitol production can be used ( see, for example, US 5,998,181 and US 5,686,277). Xylitol can be produced as a co-product during fermentative ethanol production by a simple yeast strain, using material containing hydrolyzed lignocellulose (see for example US2003/0235881). Xylonic acid can be produced from xylose with a recombinant fungal strain that is genetically engineered to express a gebe of xylose dehydrogenase, which is capable of converting xylose to xylonolactone, coupled with production of Xylitol when the fungal host is selected from the genera Saccharomyces, Kluyveromyces, Candida and Aspergillus (see for example WO 2010/106230). While other genetically engineered organisms have been described to ferment xylose, or a sugar mixture to produce Xylitol, many show insufficient productivity to be viably commercialized. In some examples, the refined hemicellulose sugar stream (eg, the fermentation feedstock) is fed into a fermentation unit seeded with the selected species at 1040% DS, such as 14-28% DS. In some examples, the microorganism selectively reduces xylose to Xylitol, without producing other polyols resulting from monosaccharides other than xylose in the fermentation broth.

[0080] The refined hemicellulose sugar stream can be added to a fermentation unit containing fermentation medium. The fermentation medium can comprise nutrients, including, for example, tryptone, yeast extract, potassium phosphate, sodium chloride, and magnesium sulfate. The fermentation unit can be inoculated with a culture of a suitable microorganism, optionally, to a final concentration of 10-40% DS. In some examples, the temperature of the fermentation unit is maintained at a temperature suitable for the microorganism, such as 25 to 35°C. Optionally, the pH of the fermentation solution is maintained at pH 6.0 to pH 8.0, such as about pH 7.0. The pH can be adjusted using NH4OH. Optionally, the fermentation solution is agitated, such as by introducing air. In some examples, additional refined hemicellulose sugar stream is added. In some examples, hexoses, such as glucose, are added to the fermentation solution. The additional refined hemicellulose sugar stream can be added 6 hours, 8 hours, 10 hours, 12 hours, 16 hours, 20 hours, 24 hours, 36 hours, or 48 hours after adding the microorganism to the fermentation unit. The fermentation process may be allowed to operate for at least 12 hours, at least 18 hours, at least 24 hours, at least 36 hours, at least 48 hours, at least 60 hours, at least 72 hours, at least 80 hours, at least at least 84 hours, at least 96 hours, or at least 108 hours, before recovery of Xylitol from the fermentation broth.

[0081] A microorganism described herein can convert the fermentation raw material into a fermentation broth comprising Xylitol. The fermentation broth may comprise at least 50 g/L, at least 60 g/L, at least 70 g/L, at least 80 g/L, at least 90 g/L, at least 100 g/L, at least 110 g/L, at least 120 g/L, at least 130 g/L, or at least 140 g/L Xylitol. Optionally, the fermentation broth comprises between 50 and 140 g/L of Xylitol, such as 60 to 100 g/L, 70 to 100 g/L, 80 to 100 g/L, or 70 to 90 g/L of Xyl - fool. In some instances, the microorganism produces little to no ethanol. Optionally, the fermentation broth comprises less than 15 g/L, less than 12 g/L, less than 10 g/L, less than 9 g/L, less than 8 g/L, less than 7 g/L, less than 6 g/L, less than 5 g/L, less than 4 g/L, less than 3 g/L, less than 2 g/L, or less than 1 g/L of ethanol. In some examples, the fermentation broth comprises xylose in an amount of less than 50 g/L, less than 40 g/L, less than 30 g/L, less than 20 g/L, less than 10 g/L, less than 8 g/L, less than 6 g/L, less than 4 g/L, less than 3 g/L, less than 2 g/L, less than 1 g/ L, less than 0.5 g/L, or less than 0.2 g/L. Optionally, the fermentation broth comprises glucose in an amount less than 35 g/L, less than 25 g/L, less than 15 g/L, less than 10 g/L, less than 8 g/L , less than 6 g/L, less than 4 g/L, less than 3 g/L, less than 2 g/L, less than 1 g/L, less than 0.5 g/L , or less than 0.2 g/L. In some examples, the fermentation broth comprises furfural in an amount of up to 1000 ppm, up to 750 ppm, up to 500 ppm, up to 400 ppm, up to 300 ppm, up to 200 ppm, up to 100 ppm, up to 50 ppm, or up to 10 ppm. Optionally, the fermentation broth comprises between 1 ppm and 1000 ppm furfural, such as 1 ppm to 250 ppm furfural. In some examples, the fermentation broth comprises less than 1000 ppm, less than 750 ppm, less than 500 ppm, less than 400 ppm, less than 300 ppm, less than 200 ppm, less than 100 ppm , less than 50 ppm, or less than 10 ppm of calcium. Optionally, the fermentation broth comprises between 1 ppm and 1000 ppm calcium, such as 1 ppm to 250 ppm calcium. In some examples, the fermentation broth comprises less than 1000 ppm, less than 750 ppm, less than 500 ppm, less than 400 ppm, less than 300 ppm, less than 200 ppm, less than 100 ppm , less than 50 ppm, or less than 10 ppm of organic acids, such as acetic acid, levulinic acid, formic acid, and lactic acid. Optionally, the fermentation broth comprises between 1 ppm and 1000 ppm of organic acids, such as 1 ppm to 1000 ppm of acetic acid. Optionally, the fermentation broth comprises between 1 ppm and 1000 ppm formic acid. In some examples, the fermentation broth comprises a C6-12 monoalcohol in an amount of up to 1000 ppm, up to 750 ppm, up to 500 ppm, up to 400 ppm, up to 300 ppm, up to 200 ppm, up to 100 ppm, up to 50 ppm, or up to 10 ppm. Optionally, the fermentation broth comprises between 1 ppm and 1000 ppm of said C6-12 monoalcohol, such as 1 ppm to 250 ppm of said C6-12 monoalcohol. In some examples, the fermentation broth comprises: at least 60 g/L of Xylitol; less than 50 g/L xylose; less than 10 g/L ethanol; less than 50 g/L of hexoses; furfural in an amount up to 1000 ppm; and less than 200 ppm of calcium. In some examples, the fermentation broth additionally comprises less than 1000 ppm acetic acid and less than 1000 ppm formic acid. Optionally, the fermentation broth further comprises a C6-12 monoalcohol in an amount of up to 100 ppm. Optionally, the fermentation broth comprises less than 100 ppm of galactitol, such as less than 50 ppm, less than 10 ppm, less than 1 ppm, or less than 1 ppb of galactitol. In some examples, galactitol is not detected in the fermentation broth. In some examples, the fermentation broth comprises a microorganism described herein. Optionally, the microorganism is selected from naturally occurring bacteria, recombinant bacteria, naturally occurring yeast, recombinant yeast, and fungi. The microorganism can be an E. coli strain, such as HZ 1434, ZUC220, ZUC170, ZUC136, HZ 2061, or HZ 2062.

[0082] Optionally, the yield of Xylitol in the fermentation broth is more than 90%, more than 91%, more than 92%, more than 93%, more than 94%, more than 95%, greater than 96%, greater than 97%, or greater than 98% relative to the amount of xylose in the refined hemicellulose sugar stream. In some examples, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least at least 95%, at least 96%, at least 97%, or at least 98% of the xylose in the lignocellulose-containing biomass is converted to Xylitol. Optionally, the amount of arabitol in the fermentation broth is less than 10% of the total polyols. Optionally, the amount of hexoses is reduced to less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4% , less than 3%, less than 2%, or less than 1% of the concentration of hexoses in the fermentation feedstock or refined hemicellulose sugar stream. Optionally, fermentation produces Xylitol at a rate of at least 1 g/L/hr, at least 2 g/L/hr, at least 3 g/L/hr, at least 4 g/L/hr, at least 5 g /L/h, at least 6 g/L/h, at least 7 g/L/h, or at least 8 g/L/h. In some examples, fermentation takes less than 120 h, less than 110 h, less than 100 h, less than 90 h, less than 80 h, less than 70 h, less than 60 h , less than 50 hours, less than 40 hours, less than 30 hours, less than 20 hours, less than 15 hours, or less than 10 hours, at least 50 g/L, at least 60 g/ L, at least 70 g/L, at least 80 g/L, at least 90 g/L, at least 100 g/L, at least 110 g/L, at least 120 g/L, at least 130 g/L , or at least 140 g/L of Xylitol (per liter of fermentation broth). Optionally, the fermentation produces at least 60 g/L of Xylitol in less than 80 hours of fermentation, such as 70 g/L of Xylitol in less than 80 hours. Optionally, fermentation produces at least 100 g/L of Xylitol in less than 80 hours of fermentation.

[0083] Xylitol can be recovered from the fermentation broth by any suitable method (1910), such as filtration, crystallization, or chromatographic separation, or a combination thereof. The fermentation broth can be filtered or centrifuged to remove the microorganism. In some examples, the filtration comprises three steps, including microfiltration, ultrafiltration, and nanofiltration. The fermentation broth may be subjected to microfiltration, optionally followed by ultrafiltration, optionally followed by nanofiltration. Filtration can remove the microorganism from the fermentation broth. Nanofiltration can remove residual disaccharides and oligosaccharides from the fermentation broth. In some examples, filtration removes at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90 %, at least 95%, or at least 98% weight/weight of oligosaccharides having a degree of polymerization of three (DP3) or more from the fermentation broth. In some examples, filtration removes at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90 %, at least 95%, or at least 98% weight/weight of disaccharides (DP2) from the fermentation broth. The filtered solution may be contacted with at least one of the following: activated carbon, such as granulated active carbon (GAC); and ion exchange resins, such as strongly acidic cation resins (SAC), weakly basic anion resins (WBA), and mixed bed resins (MB). The filtered and optionally refined solution can be concentrated by evaporation (1915) to increase the dissolved solids concentration to at least 50%, at least 60%, at least 70%, or at least 80% weight/weight solids dissolved, such as about 80% weight/weight dissolved solids. In some examples, the concentration of the solution is about 70% to about 90% weight/weight dissolved solids, such as 75% to 85% weight/weight.

[0084] The solution can be introduced batchwise or continuously into a Xylitol (1920) crystallization unit. Optionally, ethanol is added to a specified concentration, such as 0-40% wt/wt ethanol. Optionally, the solution is seeded with Xylitol crystals and gradually cooled at a controlled rate under stirring to induce crystallization. Xylitol crystals can be collected by filtration or centrifugation. Optionally, the collected Xylitol crystals are washed and dried (1960). Optionally, the collected Xylitol crystals are re-dissolved (1940) to form a Xylitol solution. The Xylitol solution can be further polished (1950), and the polished solution used as liquid Xylitol product (1950-A). Polishing can include contacting the Xylitol solution with an ion exchange resin, such as SAC, WBA, and MB resins. Optionally, the polishing includes contacting the Xylitol solution with granulated active carbon.

[0085] The mother liquor from Xylitol crystallization can be concentrated by evaporation (1922) to at least 70% weight/weight dissolved solids, such as 80% to 88% weight/weight dissolved solids. Optionally, the mother liquor is removed by evaporation to remove ethanol, if present (1928). The concentrated mother liquor can be introduced into a second Xylitol crystallization unit (1925), and can optionally be seeded with Xylitol crystals. Gradual cooling at a controlled rate can result in a second crystallization of Xylitol. These crystals (1925-A) can be collected by filtration or centrifugation. The second crystallization can produce crystals of lower purity than the first crystallization. In some examples, the mother liquor from the second crystallization is separated by chromatography (1930) to produce an extract stream comprising a composition similar to the first mother liquor, a raffinate stream that is low in Xylitol and high in arabitol, and a third stream comprising residual reducing sugars and residual oligomers. The extract stream can be recycled to the second crystallization unit to increase the total Xylitol yield. Optionally, the extract stream is removed by evaporation to remove ethanol, if present. Optionally, the third stream comprising residual reducing sugars is recycled to fermentation. Optionally, the third stream is removed by evaporation to remove ethanol, if present (1935). Optionally, the raffinate stream comprising arabitol is fed into an anaerobic digester to convert the organic matter to methane which can be used as an energy source. Optionally, the raffinate stream is removed by evaporation to remove ethanol, if present (1936).

[0086] In some examples, the recovery of Xylitol from the fermentation broth comprises: (i) filtering the fermentation broth through a microfilter and collecting the resulting microfiltrate; (ii) filtering the microfiltrate through an ultrafilter and collecting the resulting ultrafiltrate; (iii) filtering the ultrafiltrate through a nanofilter and collecting the resulting nanofiltrate; (iv) contacting the nanofiltrate with an ion exchange resin, thereby producing a refined nanofiltrate; (v) concentrating the refined nanofiltrate by evaporation, thereby producing a concentrated nanofiltrate; (vi) crystallize the Xylitol from the concentrated nanofiltrate; and (vii) separating Xylitol crystals from the mother liquor. Optionally, recovering the Xylitol from the fermentation broth further comprises: (viii) dissolving the Xylitol Crystals to form a Xylitol solution; and (ix) polishing the Xylitol solution with an ion exchange resin.

[0087] The recovered Xylitol product may comprise at least 95% weight/weight Xylitol, such as at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, or at least 99.9% weight/weight Xylitol. The Xylitol product can be produced by a method described herein. Optionally, the Xylitol product comprises less than 1% weight/weight of oligosaccharides, such as less than 0.5%, less than 0.25%, less than 0.1%, less than 0.05 %, or less than 0.01% weight/weight of oligosaccharides. Optionally, the Xylitol product comprises hexoses in an amount of up to 1% weight/weight, such as up to 0.5%, up to 0.25%, up to 0.1%, up to 0.05%, or up to 0.01% weight/weight of hexoses. The hexoses can be selected from glucose, galactose, mannose, and fructose. Optionally, the Xylitol product comprises less than 100 ppm arabitol, such as less than 50 ppm, 10 ppm, 1 ppm, or 1 ppb arabitol. Optionally, the Xylitol product comprises less than 100 ppm of galactitol, such as less than 50 ppm, 10 ppm, 1 ppm, or 1 ppb of galactitol. In some instances, galactitol is not detected in the Xylitol product. Optionally, the Xylitol product comprises ash in an amount of up to 0.25% weight/weight, such as up to 0.1%, up to 0.05%, or up to 0.01% weight/weight ash. Optionally, the Xylitol product comprises furfural in an amount up to 500 ppm, such as up to 250 ppm, 100 ppm, 50 ppm, 10 ppm, or 1 ppm of furfural. Optionally, the Xylitol product comprises an amine in an amount of up to 500 ppm, such as up to 250 ppm, 100 ppm, 50 ppm, 10 ppm, or 1 ppm amine, and wherein the amine comprises at least 12 carbon atoms. Optionally, the Xylitol product comprises a C6-12 monoalcohol in an amount up to 500 ppm, such as up to 250 ppm, 100 ppm, 50 ppm, 10 ppm, or 1 ppm C6-12 monoalcohol. In some examples, the Xylitol product is provided in crystalline form. In some examples, the Xylitol product is provided as an aqueous solution. Optionally, the concentration of the aqueous solution is at least 50% weight/weight dissolved solids, for example, about 70% to about 90% weight/weight dissolved solids, such as 75% to 85% weight/weight.

[0088] The total recovery yield of Xylitol by a separation of Xylitol from the object methods can be more than 70%, more than 75%, more than 80%, more than 85%, more than 86%, more than 87%, more than 88%, more than 89%, more than 90%, more than 91%, more than 92%, more than 93%, more than 94%, more than than 95%, greater than 96%, greater than 97%, or greater than 98% Xylitol. In some examples, the yield of Xylitol recovered by the object methods is at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, or at least 98% Xylitol relative to the xylose content of biomass containing lignocellulose.

[0089] Xylitol can be separated from a mixed sugar solution by simulated moving bed ion exclusion chromatography (SMB) using an ion exchange resin (see, for example, U.S. Pat. No. 6,451,123) . An improved system and method for the fractionation of Xylitol by an industrial scale simulated moving bed chromatography (SSMB) can be used (see, for example, US App. No. 14/398,444). Alternatively, a SAC resin can be used for the separation of Xylitol from a polyol mixture (see, for example, US Pat No. 4,008,285), in which the salt of the resin is selected from the group consisting of salts of alkaline earth metal (for example Sr2+ salts, Ca2+ salts), Fe3+ salts and Al3+ salts. In some examples, a similar SSMB method is applied to produce a Xylitol enriched stream, an arabitol stream and a reducing sugar stream comprising monomers and oligomers. The Xylitol enriched stream is recycled to the crystallizer feed such that the Xylitol yield is maximized. The reducing sugar stream is optionally removed from residual ethanol, if present, and recycled to the fermentation unit. The arabitol stream is removed from residual ethanol, if present, and is fed to a waste treatment process comprising an anaerobic digester to produce methane which can be used as an energy source for the process.

[0090] A chromatographic fractionation to achieve Xylitol concentration enrichment can be performed with ion exchange resins (for example, a cation exchange resin and an anion exchange resin) as the column packing material. Cation exchange resins include strong acid cation exchange resins. Strong acid cation exchange resins can be in a monovalent or multivalent metal cation form, for example, in the form of H+, Mg2+, Ca2+, Sr2+ or Zn2+. Strong acid cation exchange resins typically have a styrene backbone, which is preferably cross-linked with 3 to 8%, preferably 5 to 6.5% divinylbenzene. Weak acid cation exchange resins may be in monovalent or multivalent metal cation form, for example, H+, Mg2+, Ca2+, Sr2+, or Na+ form. Suitable resins can be purchased from Lanxess AG, Purolite, Dow Chemicals Ltd. or Rohm & Haas.

[0091] A chromatographic fractionation can be performed in a batch mode, a simulated moving bed (SMB) mode, or a sequential simulated moving bed (SSMB) mode. The temperature of the chromatographic fractionation is typically in the range of 20 to 90°C, such as 40 to 65°C. The pH of the solution to be fractionated can be acidic or adjusted to a range of pH 2.5 to 7, preferably 3.5 to 6.5, and more preferably 4 to 5.5. Fractionation can be carried out with a linear flow rate of about 1 m/h to about 10 m/h in the separation column.

[0092] Fig. 7 shows a pulse test showing the separation of Xylitol from an aqueous mixture comprising Xylitol, arabitol, xylose and ethanol, indicating the ability to fractionate Xylitol by SSMB. The resin is a SAC resin in the Sr2+ form.

[0093] A biomass materialized in a method or object system disclosed here can be sugarcane bagasse. In some examples, the biomass may comprise sugar cane leaves. While it may be desirable to return some sugarcane leaf mass back to the dolo after collection, excess sugarcane leaf mass can be problematic. Many technicians in the subject currently consider that sugar cane leaves are waste that need to be treated in solutions that are harmful to the environment, such as burning. Sugar cane leaves entering the sugar mill can reduce production capacity and increase sucrose losses to the outgoing fiber (ie bagasse). It may therefore be advantageous for the sugarcane growers and/or the sugar mill to use leaves as a source of hemicellulosic sugars. Currently, some of the leaves can be processed through the sugar mill. Since the sucrose content in the leaves is low, they effectively reduce the productivity of the sugar mill. In some instances, the leaves are separated from the collected canes by air sorting to separate the light leaves from the heavy cane. In some examples, the leaves are collected in the field, baled, and then transferred directly to the washing plant for processing. Sugarcane leaves can be processed similarly to sugarcane bagasse or mixed with bagasse for processing.

[0094] If a high xylose raw material other than sugarcane bagasse or leaves is used, for example birch or eucalyptus, the washing step may be unnecessary, and the system adapted accordingly by replacing the washing unit with a peeling and dimensioning system. The hemicellulose extraction unit and methods disclosed herein are particularly suitable for recovering the hemicellulose sugars comprising xylose from prehydrolysates produced in the dissolution of pulp mills in the production of cellulosic fibers, for example, viscose and acetate. Pre-hydrolysis is applied in dissolving pulp mills to remove hemicellulose from the biomass before a Kraft or sulphite pulping. Dissolving pulps typically contain low levels of residual hemicellulose (e.g., up to 3%, up to 2% or up to 1% weight/weight hemicellulose), compared to high levels in typical paper grade Kraft pulp, typically around 10 %. Typically, pre-hydrolysis is conducted in diffusion pulp digesters by treating the wood chips with steam or water to induce self-hydrolysis. Steam hydrolysis can result in the hydrolyzate being held by the pores of the wood. Hydrolysis in water may allow collection of the formed hydrolysate in higher yields. Optionally, an acid can be added to the water to accelerate the hydrolysis of the hemicellulose. Optionally, the acid can be a mineral acid or an organic acid, for example SO2 , H2SO4 , HCl, acetic acid, or formic acid. Since the prehydrolysis conditions can be severe enough to optimally remove hemicellulose from the biomass, the resulting hydrolyzate can be relatively high in degradation products. Nevertheless, the hydrolyzate can be refined, and xylose and/or Xylitol can be collected in the systems and methods disclosed herein, thereby enhancing the hydrolyzate stream and contributing significantly to mill economy. Optionally, the system disclosed herein can be combined with pulp mill dissolution for chemical recovery, solvent recycling, and waste stream energy harvesting, thereby reducing the production cost of both hemicellulose sugars. and the dissolving pulp. Optionally, hexoses are added to the hydrolyzate prior to fermentation to achieve the preferred ratios of xylose to hexoses as described above for the refined hemicellulose sugar stream and the fermentation feedstock.

[0095] In one aspect, the disclosure provides a system for producing Xylitol from a lignocellulose-containing biomass. In one example, the system comprises: (i) a hemicellulose extraction unit configured to extract and hydrolyze hemicellulose from biomass to produce a hemicellulose sugar stream and a lignocellulose remnant stream; (ii) a refining unit in fluid communication with an extraction unit, in which the refining unit is configured to receive the hemicellulose sugar stream and an amine extracting agent, and in which the amine extracting agent removes impurities from the hemicellulose sugar stream to produce a refined hemicellulose sugar stream; optionally, (iii) a detection unit configured to analyze one or more parameters of the refined hemi-cellulose sugar stream, in which the one or more parameters are selected from pH, light absorbance, conductivity, density, xylose concentration, and hexose concentration; (iv) a fermentation unit in fluid communication with the refining unit to receive the refined hemicellulose sugar stream, in which the fermentation unit is configured to contain the refined stream and a microorganism, and in which the microorganism facilitates the Xylitol production of a monosaccharide in the refined stream to produce a fermentation broth; and (v) a Xylitol refining unit, in which the Xylitol refining unit is configured to remove Xylitol from the fermentation broth.

[0096] Optionally, the system additionally comprises a washing unit configured to remove ash and soil from the biomass. The washing unit may be in fluid communication with the hemicellulose extraction unit. Optionally, a backwash unit, as shown in Fig. 8 is used for soil removal and biomass ash removal. A method for reducing ash content and soil content may comprise at least one and up to n stages of re-fluidizing and grinding (e.g. grinding) the biomass, and at least one and up to m stages of washing and dewatering the biomass , where n is 2, 3, 4, 5, 6, 7, 8, 9 or 10 and m is 2, 3, 4, 5, 6, 7, 8, 9 or 10. Optionally, n equals m. In some examples, m is greater than n, or n is greater than m.

[0097] Each stage of a washing unit used to reduce the soil content and ash content of a biomass may comprise a tank, in which the biomass is re-fluidized by means of an agitator, a pump, or any other means capable of causing re-fluidization of biomass in water. Optionally, the liquid to solid ratio in the tank is 30-60:1, such as a liquid to solid ratio of 60 to 1, 55 to 1, 50 to 1, 45 to 1, 40 to 1, 35 to 1, or 30 to 1. Each tank can be equipped with a solids inlet. The tank may be in fluid communication, for example via a pump and a pipe, with a dewatering device, in which the slurry in the tank can be transferred to the dewatering device. The washing unit may comprise a tube for returning the liquid phase from the dewatering device to the tank. Optionally, the dewatering device is positioned higher than the tank so that gravity can assist in returning the liquid to the tank. In some examples, each tank is equipped with a liquid inlet connected to receive liquid from its stage n+1, and a liquid discharge connected to distribute liquid to its stage n-1, where the liquid discharge of stage I can be connected to deliver liquid to an auxiliary tank for water recycling. The liquid discharge position can be at the top of the liquid phase in the tank of each stage, such that the liquid is transferred as an overflow stream. Optionally, the n-stage tank comprises an additional water intake connected to receive a stream of water. Optionally, the water stream comprises filtered or treated recycled water from the wash unit, fresh water, or process water from other units in the system.

[0098] An auxiliary tank of the washing unit can receive a purge stream. The purge current can come from the sequential overflow or from the bottom purge of the tanks, in a continuous or intermittent mode. Optionally, the auxiliary tank is connected to at least one device for separating fine particles from the liquid, such as a hydrocyclone, a centrifuge, or a filter. A hydrocyclone or centrifuge can be used to recover fine biomass particles from the top discharge. This recovered biomass can be sent to the n-stage tank to minimize biomass losses. Ash and soil particles can be separated from the bottom discharge, or the higher density discharge (however, positioned in the used separation device). This stream can be further filtered to remove soil and recover water.

[0099] The tank of each stage can also be equipped with a low-level liquid/solid discharge, preferably positioned at the bottom of the tank. Optionally, the system is also equipped with at least one pressurized air intake. One or more stages may be equipped with a grinding or grinding device, which device is optionally an in-line submerged grinding or grinding device. In some examples, the crushing or grinding is increasingly finer with each progressive stage n in the washing unit. Several manufacturers offer suitable crushing, grinding, homogenizing and pulping devices including, for example, EBERA Fluid Handling, Bolton Emerson, ARDE-BARINKO and IKA. Different devices can be used at different stages.

[00100] Optionally, at least one dehydration device comprises a sieve. The sieve size can vary between 1000 and 100 micrometers. Optionally, the sieve size is decreased with each progressive m stage in the washing unit. The sieve can be held in a diagonal position, or in a curved position with respect to the ground. Biomass can be collected from the top of the screen and transferred through the solid transfer chute to the n+1 stage tank. A liquid comprising solid particles and fine biomass particles can pass through the sieve, and can be returned to the n-stage tank. Several manufacturers offer suitable screening devices, including, for example, Dorr-Oliver and FluidQuip. Different devices can be used at different stages.

[00101] In some examples, a dewatering device may be connected to another dewatering device directly (ie, not through another tank). Optionally, the final dewatering device m applies pressure to reduce water content to a minimum. In some examples, the final water content of the washed biomass may be less than 70, less than 65, less than 60, less than 55, less than 50, less than 45, less than 40, less than 35, or less than 30% weight/weight. In some examples, the final water content of the washed biomass is 40-60% weight/weight. The final dewatering device may comprise a screw press. A suitable screw press may comprise either a single screw or twin screw or a twin screw or cylinder mill which achieves the final water content at the desired production rate. Several manufacturers offer suitable screw press devices including, for example, Vincent Corporation, Stord Bartz, FKC Company Ltd and Parkson Corporation. Different devices can be used at different stages.

[00102] The raw biomass can be received by the upstream collection or treatment washing unit in shavings, pieces, or particles of various sizes. Optionally, the created biomass is first shredded or chopped to break up chunks and scale the raw biomass to uniform size which can be re-fluidized and handled by pumps and mills further downstream. Systems suitable for crushing or cutting can be selected from, but are not limited to, a jaw crusher, a cone crusher, a crusher, a hammer mill, and a shredder. Numerous manufacturers offer such equipment, including, for example, West Salem Machinery, Metso Corporation and Andritz. Optionally, the raw biomass is sized as greater than 70, 75, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, or greater than 99% weight/weight through a 20 mesh (841 micrometer) sieve. Optionally, the raw biomass is sized such that greater than 70, 75, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, or greater than 99% weight/weight through a 12 mesh (1680 micrometer) sieve. Optionally, the raw biomass is sized such that greater than 70, 75, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, or greater than 99% weight/weight through a 7 mesh (2830 micrometer) sieve. Optionally, the raw biomass is sized such that greater than 70, 75, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, or greater than 99% weight/weight through a 5 mesh (4000 micrometer) sieve. In some examples, greater than 93% weight/weight through a 12 mesh screen and greater than 90% weight/weight through a 20 mesh screen. In some examples, about 20% (weight/weight) ) of the material is retained on a 60 mesh (250 micrometer) sieve, and about 20% (weight/weight) is retained on a 40 mesh (400 micrometer) sieve. In some examples, less than 4%, less than 5%, less than 6%, less than 7%, less than 8%, less than 9%, less than 10%, less than 11 %, or less than 12% weight/weight through a 200 mesh (7480 micrometer) sieve. The sized biomass can be transferred by any solid material transfer medium, and can be fed to the stage I tank of the washing unit.

[00103] A system described herein may comprise a hemicellulose extraction unit configured to extract and hydrolyze hemicellulose from biomass to produce a hemicellulose sugar stream and a lignocellulose remnant stream. A hemicellulose extraction unit may comprise a tank equipped with a solid feed device and at least one aqueous feed device, in which the tank can maintain a pressure of at least 400 psi, and can be heated to a temperature of at least 250°C. The tank can be equipped with stirring capability to mix solid and liquid streams. Optionally, the tank is equipped with flow capability to move solid and liquid streams. The tank may be equipped with a suitable discharge for removing the reacted slurry. An extraction unit tank may optionally have more than one compartment in which adjacent compartments are separated by dams. Optionally, the extraction unit may comprise more than one tank, in which the tanks are in fluid communication with adjacent tanks to allow the mass to flow through consecutive tanks. In some examples, the extraction unit comprises a piston reactor. The reactor piston can be mounted at a low angle to assist in the reactor emptying when a shutdown is required. The reactor can be partially or completely lined to prevent heat loss.

[00104] An aqueous slurry comprising the biomass can be fed continuously to the hemi-cellulose extraction unit. In some examples, the acid concentration of the aqueous slurry is monitored. Optionally, additional acid is added if the acid concentration is below a threshold. Optionally, said monitoring is continuous, and said acid addition is controlled by a computerized system that accepts the admission of at least one probe, in which the computerized system additionally controls pumps and valves of the system. Optionally, the extraction product, for example a hemicellulose extraction slurry comprising hemicellulose sugars, is continuously removed. In some instances, the aqueous slurry fed to the extraction unit may be heated in the incoming stream. Optionally, the slurry is heated in an extraction unit tank. In some examples, a stream exiting the extraction unit (for example, a hemicellulose extraction slurry) is cooled. Heating or cooling processes can be fast, for example flash heating and/or flash cooling. Optionally heating to extraction setpoint is done at less than 60, less than 45, less than 30, less than 25, less than 20, less than 15, less than 10, or less than 5 minutes. Optionally, cooling the extraction slurry is done at less than 60, less than 45, less than 30, less than 25, less than 20, less than 15, less than 10, or less than that 5 minutes. The heat removed at the cooling end can be used to heat the heating end by using suitable heat exchangers, for example spiral shell and tube, standard shell and tube, or a plate and frame. Suitable heat exchangers can be obtained, for example, from Alfa Laval or Chemineer Inc. In some examples, the extraction unit is used to conduct a batch or, preferably, continuous process to extract hemicellulose, organic acids, and fly ash and biomass extractives.

[00105] In some examples, the hemicellulose extraction slurry comprises hemicellulose sugars and lignocellulose residue. The hemicellulose extraction unit may comprise a system for separating a remaining lignocellulose stream from the hemicellulose sugar stream. Optionally, the remaining lignocellulose stream is washed to remove residual hemicellulose sugars. Optionally, the hemicellulose sugar stream is washed to remove residual lignocellulose components. A system for separating solids, such as the remaining lignocellulose stream, from liquids, such as the hemicellulose sugar stream, after hemicellulose extraction is shown in Fig. 9. This system may comprise at least one solid-liquid separation device. In some examples, the system comprises at least one refluidization tank. More than one solid-liquid separation step and re-fluidization step can optionally be conducted with the washing liquid applied in a counter current manner. The system may comprise 1, 2, 3, 4, 5, or 6 solid-liquid separation steps, followed by re-fluidization steps. Solid-liquid separation devices can be selected from curved screens, settling tanks, centrifuges, and hydrocyclones. In some examples, the final wash step is conducted in a centrifuge. The liquid collected in the heaviest load can be transferred to the extraction liquid feed.

[00106] The remaining lignocellulose stream can be separated from the hemicellulose sugar stream by means of a vacuum belt filter. Vacuum belt filter systems are commercially available from a number of suppliers including, for example, Pannevis, BHS-Sonthofen Inc. and FLSmidth. In some examples, the extraction slurry is continuously fed over a moving belt. As the belt moves, vacuum can be applied to remove liquids, and create a filter cake that settles on the moving belt. Optionally, the belt passes through a washing zone. Optionally, the belt passes through a drying zone. A wash zone may comprise nozzles that spray a wash fluid onto the filter cake (i.e., the remaining lignocellulose stream) to rinse residual hemicellulose sugars from the remaining lignocellulose stream, thereby increasing recovery. of hemicellulose sugars. The temperature of extraction slurry and washing fluid can be about 20-100°C, such as 30-90°C, 35-85°C, 3580°C, 40-80°C, 50-80°C , 40-75°C, or 55-75°C. Optionally, the flushing fluid is water. Flush flow rate can be about 0.25, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1 compared to slurry flow extraction fluid. In some examples, less than 40%, less than 30%, less than 20%, less than 10%, less than 5%, less than 4%, less than 3%, less than 2 .5%, less than 2%, less than 1.5%, or less than 1% of the solids remain in the hemicellulose sugar stream. In some examples, the belt is moved over a roller to cause the filter cake (i.e., the remaining stream of lignocellulose) to fall. Optionally, residual solids are scraped off the belt with scrapers. More than about 60%, more than about 70%, more than about 80%, more than about 90%, or more than about 95% of the solids in the extraction slurry can be recovered in the remaining stream of lignocellulose. After removing the remaining lignocellulose stream, the belt can be moved back to the starting rollers at the beginning of the line. A vacuum belt can be manufactured from a variety of materials using different fabric production methods, and can be woven or non-woven. Fabrication can be optimized to produce the desired porosity, thickness, and air permeability.

[00107] A system described herein may comprise a refining unit in fluid communication with the extraction unit, in which the refining unit is configured to receive the hemicellulose sugar stream and an amine extracting agent, and in which The amine extracting agent removes impurities from the hemicellulose sugar stream to produce a refined hemicellulose sugar stream. Optionally, the hemicellulose sugar stream is extracted with an amine extracting agent countercurrently, e.g., the hemicellulose sugar stream flows in an opposite direction to the flow of the amine extracting agent. The refining unit may comprise a mixer-decanter device, an agitated tank, a liquid-liquid separation centrifuge, or a column, in which the mixer-decanter device, agitated tank, liquid-liquid separation centrifuge, or a column, It is equipped with a liquid feeding device to receive the hemicellulose sugar stream from the extraction unit. The refining unit can be equipped with an inlet to receive the amine extracting agent. Optionally, the amine extraction is conducted in a mixer-decanter device, where the mixer-decanter device can be designed to minimize emulsion formation, thereby reducing phase separation time. A mixer-decanter device comprises a first stage that mixes the phases together, followed by a quiescent settling stage that allows the phases to separate by gravity. Various decanter mixers known in the art can be used. In some examples, phase separation can be enhanced by incorporating a suitable centrifuge with the decanter mixer. Optionally, both mixing and separation can be conducted in a liquid-liquid separation centrifuge. Liquid-liquid separation centrifuges are commercially available from several suppliers, including, for example, Rousselet Robatel Inc. and US Centrifuge Sistemas LLC. The amine extraction can be conducted at any temperature at which the amine is soluble, such as 50-70°C. Optionally, the amine extraction comprises more than one extraction step (e.g., 2, 3, or 4 steps). The ratio of the amine extractor stream (organic stream) to the hemicellulose sugar stream (aqueous stream) can range from about 0.5:1 to about 5:1 weight/weight, such as about about 0.5:1, about 1:1, about 1.5:1, about 2:1, about 2.5:1, about 3:1, about 3.5:1, about of 4:1, about 4.5:1, or about 5:1. In some examples, the ratio of organic stream to aqueous stream is about 1.5-4.0:1 weight/weight. The refining unit may further comprise at least one discharge for removing the refined hemicellulose sugar stream. In some examples, the refining unit further comprises column or batch units to contact the hemicellulose sugar stream with ion exchange resins, or activated carbon to further polish the refined sugar solution. In some instances, the discharge is in fluid communication with a fermentation unit. The refining unit may comprise second discharge for removing the organic stream comprising the amine extracting agent. In some examples, the organic stream is treated, and the resulting purified amine extractant recycled back to the refining unit.

[00108] A system described herein may comprise a detection unit in fluid communication with the refining unit for analyzing the refined hemicellulose sugar stream. The detection unit can analyze the refined hemicellulose sugar stream continuously, or in batches. In some examples, the detection unit comprises a pH probe. Optionally, if the pH probe detects that the pH of the refined hemicellulose sugar stream is too acidic, such as pH less than about 3.0, the detection unit can separate the stream away from the fermentation unit. In some instances, if a pH probe detects that the pH of the refined hemicellulose sugar stream is too acidic, the detection unit is set to raise the pH of the solution, for example by adding ammonia. In some examples, the detection unit analyzes the color of the refined hemicellulose sugar stream, for example using a spectrophotometer. If the absorbance of light at a particular wavelength is determined to be too high, the detection unit can separate the stream far from the fermentation unit. In some instances, the detection unit analyzes the conductivity of the refined hemicellulose sugar stream, for example using a conductivity probe. If the conductivity is determined to be very high, such as conductivity greater than 10,000 microS/cm, the detection unit can separate the stream far from the fermentation unit. In some examples, the detection unit analyzes the density of the refined hemicellulose sugar stream, for example using a refractometer. If the density is determined to be too high or too low, such as a density corresponding to a concentration outside of sugar outside the range of 50 g/L to 300 g/L, the sensing unit can separate the stream far from the fermentation, or may cause the addition of water to dilute the stream. The detection unit can be configured to analyze the concentration of one or more components of the refined hemicellulose sugar stream, in which the one or more components are selected from xylose, arabinose, hexoses, glucose, galactose, mannose, fructose, disaccharides, oligosaccharides, ash, phenolic compounds, furfural, and hydroxymethylfurfural. Any concentration outside the ranges described for the subject methods and compositions may cause the detection unit to separate the stream far from the fermentation unit, or correct the concentration by proper compensation or dilution. Any separate stream from the fermentation unit can be further refined or used in some other plant process.

[00109] A system described herein may comprise a fermentation unit in fluid communication with the refining unit to receive the stream of refined hemicellulose sugar, in which the fermentation unit is configured to contain a fermentation feedstock comprising the refined stream and a microorganism, in which the microorganism facilitates the production of Xylitol from a monosaccharide in the refined hemicellulose sugar stream to produce a fermentation broth. The fermentation unit may comprise a tank equipped with at least one aqueous feed inlet to receive the refined hemicellulose sugar stream. Optionally, the fermentation unit can be temperature controlled, such that the fermentation unit maintains a given fermentation temperature within ± 10°C, within ± 8°C, within ± 5°C, within ± 4° C, within ± 3°C, or within ± 2°C. Optionally, the fermentation unit comprises one or more sensors, such as a temperature sensor, a density sensor, or a pH sensor. Optionally, the fermentation unit comprises a density sensor, such as a refractometer, such that the specific gravity of the fermentation broth can be measured. A change in fermentation broth density above or below a certain threshold may indicate that the fermentation has consumed a desired concentration of hemicellulose sugars. A tank of the fermentation unit can be equipped with at least one discharge, such that the fermentation broth can be removed via the at least one discharge.

[00110] A system described herein may comprise a Xylitol refining unit, in which the Xylitol refining unit is configured to remove Xylitol from the fermentation broth. The Xylitol refining unit may be in fluid communication with the fermentation unit. In some examples, the Xylitol refining unit comprises one or more filters, such as microfilters, ultrafilters, and nanofilters. Optionally, the Xylitol refining unit comprises three filtration stages, such that the fermentation broth is subjected to microfiltration, ultrafiltration, and nanofiltration. The one or more filters may be in fluid communication with one or more columns, in which case the one or more columns may contain activated carbon, such as granulated active carbon, or an ion exchange resin, such as a strongly acidic cation resin. , weakly basic anion resin, or mixed bed resin. Optionally, the one or more columns are in fluid communication with an evaporation unit, wherein the evaporation unit is configured to evaporate water from solution, thereby increasing the concentration of dissolved solids. Optionally, the Xylitol refining unit comprises a Xylitol crystallization unit. The Xylitol crystallization unit may be in fluid communication with the evaporation unit. In some examples, the Xylitol crystallization unit comprises a means for stirring the solution. Optionally, the Xylitol crystallization is temperature controlled, such that the temperature of the unit can be gradually cooled down. The Xylitol crystallization unit may additionally comprise an inlet for receiving ethanol. In some examples, ethanol is added to the solution in the Xylitol crystallization unit to aid in the Xylitol crystallization. In some examples, the Xylitol crystallization unit is configured to receive feed solution from the evaporation unit in batch or continuous mode. The Xylitol crystallization unit may comprise a sieve or filter to facilitate the separation of Xylitol crystals from the mother liquor by filtration, or it may be in fluid communication with a filter or centrifuge configured to receive the crystallization slurry. The separated Xylitol crystals can be re-dissolved, and the resulting Xylitol solution transferred to a Xylitol polishing unit. In some examples, the Xylitol polishing unit comprises an ion exchange resin, such as a SAC, WBA, or MB resin. Optionally, the Xylitol polishing unit comprises active carbon, such as granulated active carbon.

[00111] In some examples, the units described are connected such that the mass is transferred through the sequential process steps. The solid feed unit can transfer solid bagasse mass to a sizing mill either batchwise or continuously. The sizing unit can be configured to either batch or continuously transfer sized bagasse mass to the washing unit. This washing unit (1770) can be connected such that the washed bagasse solid mass is transferred to the hemicellulose extraction unit either continuously or in batches. Optionally, the washing unit is also connected to a dump stream which allows removal of a solid dump stream comprising the removed soil and ash to a disposal location. The washing unit can optionally be connected to other process units further downstream to receive process water. The hemicellulose extraction unit (1700) can be connected to receive bagasse mass washed by solids transfer means. Optionally, the hemicellulose extraction unit is also connected at its outlet to the refining unit via liquid transfer. The hemicellulose extraction unit can also be connected to other processes that utilize the remaining solid lignocellulose stream via solid transfer. In some examples, the refining unit (1710) is connected via liquid transfer to the hemicellulose extraction unit, fed the same extraction liquor. The refining unit can be connected by liquid transfer means to a fermentation unit (1900), fed to the same with the refined hemicellulose sugar stream as feed for Xylitol fermentation. Alternatively, this refining unit is connected to a xylose fractionation unit (1720 and 1837) via liquid transfer. A schematic diagram of exemplary conversion processes for converting a xylose-enriched hemicellulose sugar mixture (1720-P1) to downstream products is provided in Fig. 2A. The xylose fractionation unit can be connected via liquid transfer to a fermentation unit (1900), feeding it with a sugar mixture enriched with xylose for the production of Xylitol. Xylitol can be refined in a Xylitol refining plant (1920). The xylose fractionation unit is optionally connected alternatively or in addition to a xylose crystallization unit (1841) for the production of crystalline xylose (1841-P1). Crystalline xylose can be used in a catalytic conversion unit (1910) for the catalytic conversion of xylose to Xylitol, optionally crystallized in a Xylitol crystallization unit (1915) to produce Xylitol (1950-P1). The xylose fractionating unit can optionally be alternatively or additionally connected to another process (1780) for the chemical conversion of C5 sugars to furfural (1780-P1). In some examples, the xylose fractionating unit is also connected by liquid transfer means with another process capable of using the xylose-depleted sugar mixture as a feed for biochemical or chemical conversion of the sugar mixture to products. A schematic diagram of exemplary processes for converting a xylose-depleted sugar mixture (1720-P3) to a downstream product is provided in Fig. 2C. The xylose-depleted sugar mixture can undergo a second fractionation (2000) to give an arabinose product (2000-P1). The xylose-depleted sugar mixture can optionally be alternatively or additionally digested in an anaerobic digestion unit (2030) to produce methane (2030-P1). In some examples, the xylose fermentation unit is connected with the xylose fractionation unit via liquid transfer, feeding it a xylose-enriched sugar mixture as feed. The fermentation unit can be connected to the Xylitol refining unit via liquid transfer. In some examples, the Xylitol refining unit is connected to the fermentation unit by liquid transfer means, feeding it with a mixture comprising Xylitol. The Xylitol refining unit can be connected with a Xylitol crystallization unit, feeding it with refined and fractionated Xylitol through liquid transfer. The Xylitol refining unit can also be connected with another process capable of utilizing the reject stream in Xylitol fractionation via liquid transfer. The Xylitol refining unit can alternatively be connected to the fermentation unit, transferring the rejected liquid stream back to the fermentation unit for recycling nutrients and residual sugars. In a preferred example, the complete system of connected units disclosed herein operates in an orchestrated manner to result in an industrial system for producing blends of refined hemicellulose sugar, xylose, Xylitol and further products produced therefrom, efficiently and with positive economics.

[00112] In some examples, the mass transfer flow of the different connections is optimized to match the upstream and downstream flows of each flow, so that the units are optimized to be used efficiently. Energy can be transferred from unit to unit such that excess heat in one unit is used to heat another unit. Energy usage across all units revealed here can be optimized for the total process.

[00113] In some examples, water usage is optimized for the total process. Excess water produced in one unit can be transferred via liquid transfer to be used where water is needed in another unit. Optionally, acid and base usage is optimized for the total process to minimize the need for fresh acid or base. For example, acid streams resulting from the regeneration of acid wash cation exchange resins are used to regenerate Weak Acid Cation exchangers and/or acidify or neutralize streams in other units.

[00114] The system can be constructed such that it can feed at least 35,000 tons (dry solid) of sugarcane bagasse per year into the system, to produce at least 7,000 tons (dry solid) of refined hemicellulose sugars per year. The system is optionally constructed such that it can produce at least 5,000 tons (dry solid) of xylose per year, at least 2,000 tons (dry solid) partially depleted xylose sugar blend per year, together with at least 24,000 tons of dry solid ) of remaining lignocellulose. The system is optionally constructed such that it produces wastewater at about 250 gpm.

EXAMPLES

[00115] It is understood that the examples and embodiments described herein are for illustrative purposes only, and are not intended to limit the scope of the claimed invention. It is also understood that various modifications or changes in light of the examples and embodiments described herein will be suggested to those skilled in the art, and are to be included within the spirit and purpose of this application and scope of the appended claims. All publications, patents, and patent applications cited herein are hereby incorporated by reference in their entirety for all proposals.

Example 1 - Analysis of ash from Louisiana bagasse raw material before and after removal of soil and ash

[00116] The ash fraction of a bagasse sample taken from a heap in a sugar mill in Louisiana was evaluated by incineration of samples in a microwave oven (3.1. CEM Phoenix™ Microwave Muffle Furnace). The bagasse sample was found to contain 13.4% ash. Table 1A: Ash results after different treatments to remove soil and ash

[00117] The results summarized in Table 1A demonstrate the high ash present in Louisiana bagasse obtained from different sugar mills and different sampling times. The results also show that to achieve effective soil and ash removal, it is essential to apply several cycles of shear treatment and high pressure washing to cause the removal of stones, sand and ash compost suns. The remaining bagasse still retains 2-3% of “true” ash, which is related to metal cations and other elements associated at the molecular level in cell structure.

[00118] Another sample of bagasse was ground and de-ashed, and the samples sieved through a series of sieves before and after removal of ash. Table 1B: Removal of soil/Removal of ash from bagasse

[00119] The results summarized in Table 1B demonstrate the ability to industrially remove much of the soil and ash from the bagasse feedstock by shear treatment and high pressure ash, while still retaining ~85% of the original feedstock in size larger than 30 mesh, which allows for additional handling of washed material.

Example 2 - Characterization of different bagasse samples

[00120] Under practical operating conditions, an industrial process must be able to use bagasse with a varied storage history, as bagasse can be stored in piles by the sugar mill for 1, 3, 5, or even 10, 12, or 14 years. Furthermore, the sugar cane collection season is about 3 months, with sugar production being a seasonal process, whereas a bio-refinery must operate year-round. It is additionally advantageous that excess leaves and field debris can be handled in the same process to collect the xylose portion within, and to eliminate a bottleneck of debris handling for the farmer and/or sugar mill. Bagasse samples that were stored for more than one year, new bagasse and field fragments were characterized. “Novo Bagasse” samples were from piles accumulated up to 4 years ago, “Old Bagasse” samples were from piles accumulated 5-15 years ago, and “Leaves” and other field fragments were denuded of soil / depleted of ash, according to Example 1. Washed samples were heated at 160°C for 60 minutes to extract hemicellulose sugars. Lignocellulosic biomass before and after extraction was analyzed according to NREL/TP-510-42622. Both solid phases and the hydrolysis liquor were analyzed for carbohydrate composition by HPAE-PAD. The results are summarized in Table 2. The results indicate that all samples can be manipulated by the methods and systems disclosed herein. Table 2: Composition of bagasse and samples from different field fragments

Example 3 - Louisiana Bagasse Crushing

[00121] The bagasse was received from a sugar mill in pieces. The biomass was ground using a wood chipper and sieved through a series of sieves. Typical particle sizes of shredded/chopped bagasse are given in Table 3. Table 3: Particle size of shredded bagasse

Example 4 - Extraction, refining, and fractionation of biomass

[00122] The bagasse was crushed in a wood cutter. The crushed bagasse was washed in a temperature controlled tank, and the washed bagasse (60 lbs, dry basis) treated with an aqueous solution containing 0.5% H2SO4 (weight/weight) in a liquid to solid ratio of 14.2: 1. The average temperature of the temperature-controlled tank was maintained at 130-135°C for 3 hours. The solution was circulated by pumping. The resulting liquor was collected, and the solids were washed with water. The wash water was then used to prepare the acid solution for the next batch by adding acids as needed. The remaining stream of cellulose-depleted lignocellulose was collected and dried.

[00123] The acidic hemicellulose sugar stream was run through a SAC column. The sugar stream was then extracted continuously in a series of decanter-mixers (2 stages) with an amine extracting agent (30:70 trilaurylamine:hexanol). The ratio of amine extracting agent to sugar stream was kept in the range of 2:1 to 1.5:1. The resulting aqueous phase was further purified using a SAC column, a WBA resin, a granulated active carbon, and a mixed bed resin. The pH of the resulting stream was adjusted to 4.5 with 0.5% HCl, and the sugar solution was evaporated to a concentration of ~30% DS. The resulting refined hemicellulose sugar stream contained about 7% arabinose, 2.5% galactose, 6.5% glucose, 65% xylose, 1.5% mannose, 4% fructose, and 14% of oligosaccharides (all % weight/total sugars). This sugar solution was further processed by fractionation on an SSMB system, resulting in a xylose rich fraction and a xylose depleted fraction. Each fraction was concentrated by evaporation. Table 4 provides a chemical analysis of the resulting xylose-rich sugar solution. Table 4: Chemical analysis of a xylose-enriched sugar stream produced by hemicellulose sugar extraction and bagasse purification

Example 5 - Extraction and refining of biomass

[00124] Bagasse was crushed and desoiled according to Examples 1 and 3 and the refined solids separated by filtration. The collected hemicellulose sugar stream was refined by first contacting it with a SAC resin, followed by removal of many of the impurities by amine extraction. The refined aqueous sugar solution was further polished by contacting it with a SAC resin, a WBA resin and finally evaporated to a concentration above 70% weight/weight of dissolved sugars. The process was conducted on a pilot scale at Virdia PDU, Danville, VA. Table 5 summarizes the sugar profile of the refined hemicellulose sugar streams. Table 5: Sugar composition of a refined hemicellulose sugar stream produced by hemicellulose sugar extraction and bagasse purification

[00125] As shown in Table 5, a stream of refined hemicellulose sugar produced from bagasse comprises, on average, 66% xylose, 6% arabinose, and 15% hexoses, all weight/weight relative to total sugars . The streams exemplified in Table 5 are therefore suitable for use in the subject methods for conversion to Xylitol.

Example 6 - Fractionation of refined hemicellulose sugar stream

Tabela 6B: Composição de açúcar de uma mistura de açúcar exaurida de xilose produzida de bagaço

[00126] Refined hemicellulose sugar streams 1 to 10 produced according to Example 5 were fractionated by chromatography (as per PCT/US2013/039585) to produce xylose-enriched extract streams 1 to 10 (Table 6A) and xylose depleted raffinate streams 1 to 10 (Table 6B). A pulse test chromatogram showing fractionation of a refined hemicellulose sugar stream is provided in Fig. 6. This pulse test demonstrates the ability to fractionate a refined hemicellulose sugar stream to obtain a xylose spent stream, and a xylose spent stream. Table 6A: Sugar composition of a sugar blend enriched with xylose produced from bagasse

Table 6B: Sugar composition of a xylose-depleted sugar blend produced from bagasse

[00127] As shown in Table 6A, a sugar mixture enriched with xylose produced from bagasse comprises, on average, 84% xylose, 4% arabinose, and 11% hexoses, all weight/weight relative to total sugars . Some Xylose-enriched blends, such as Sample 3, have a lower concentration of hexoses (86% xylose, 5% arabinose, and 9% hexoses). On average, the samples exemplified in Table 6A are suitable for use in the subject methods for conversion to Xylitol, although some of the individual samples may contain a higher than ideal ratio of xylose to hexoses. Surprisingly, fractionation of a refined hemicellulose sugar stream may not be necessary to produce a sugar stream suitable for conversion to Xylitol.

[00128] As shown in Table 6B, a xylose-depleted sugar blend produced from bagasse comprises, on average, 20% xylose, 11% arabinose, and 26% hexoses, all weight/weight relative to total sugars.

Example 7 - Composition of sugar to feed a fermentation process

[00129] The refined hemicellulose sugar streams disclosed herein are particularly suitable as a feed for fermentation species capable of hydrogenating xylose to Xylitol with high specificity, and capable of using the C6 sugars as well as at least some of the arabinose as their source of energy for proliferation. Table 7 summarizes typical refined hemicellulose sugar streams suitable to be fed into Xylitol production. Table 7: Sugar composition of a refined hemicellulose sugar stream suitable as a feed for Xylitol fermentation

Example 8 - Crystallization of Xylitol from a model solution

[00130] The ability to purify Xylitol from a mixture containing Xylitol, arabitol, and xylose by crystallization and chromatography, was evaluated. Crystallization was performed in a stirred coated beaker attached to a circulating water heater/cooler. A solution was produced to simulate a fermentation product: 300g of a solution containing 93.9% Xylitol, 3.7% Xylose, and 2.8% arabitol/arabinose was diluted to 79.2% DS, and ethanol added, according to the total weight of solvent indicated in mol%. Crystallization was initiated at 65°C by seeding with Xylitol, and the solution cooled to 35°C for 16 h. Crystals were collected by filtration, washed with ethanol, dried, and analyzed for Xylitol purity by HPAE-PAD. Xylitol yield and purity are summarized in Table 8. It is observed that high yield of Xylitol was achieved (eg 77% in one crystallization), with Xylitol being 99.9% pure from reducing sugars and arabitol. Table 8: Yield and purity of Xylitol crystals

Example 9 - Fractionation of Xylitol from crystallization of the mother liquor

[00131] Xylitol was fractionated from a mixture containing 43% weight/weight of Xylitol, 6% weight/weight of arabitol, 6% weight/weight of xylose, and 8% weight/weight of ethanol. The composition of this mixture is representative of the major components present in the crystallization of the mother liquor.

[00132] A pulse test was conducted using 250 mL of Purolite PCR 642 (gel form, styrene divinylbenzene copolymer, functional group sulfonic acid, and average bead size 295 - 335 μm). The gel was preconditioned with a solution containing strontium salt to produce it completely in a strontium form. A 12.5 mL sample of the Xylitol mixture was injected, followed by water elution at 8.33 mL/min. Effective fractionation of Xylitol from the mixture was observed, with Xylose peaking at 0.61 BV, ethanol at 0.72 BV, arabitol at 0.84 BV, and Xylitol peaking at 0.96 BV. Pulse test results are depicted in Fig. 7. This pulse test demonstrates the ability to fractionate the mother liquor solution to obtain a Xylitol stream, arabitol stream, and sugar stream reduction.

Example 10 - Ash removal/soil removal of old and new bagasse on a pilot scale

[00133] A system as described schematically in Fig. 8 was constructed, comprising 4 sieves (Fluidquip, DSM, Screen Service) for solid/liquid separation and a final screw press (Vincent Corporation). 40 tons of bagasse from Raceland, LA, were analyzed for ash and moisture content, and found to have an ash level of 12.9 ± 1.6% weight/weight, and a moisture level of 56.6 ± 6, 6% weight/weight. The bagasse was first crushed to break up tufts, and fed into the washing unit of Fig. 8. Washed and dehydrated bagasse was collected daily for analysis of residual ash amounts. The daily results shown in Fig. 10 indicate that the scrubbing system successfully removes soil from the bagasse feed to reduce the measured ash level below 6% weight/weight.

Example 11 - Filtering, washing and dehydrating the remaining lignocellulose stream from the hemicellulose sugar stream

[00134] The washed bagasse was heated to extract the hemicellulose sugars in batches of 2000-3000 Lb under conditions similar to Example 4. The collected slurry was continuously fed into a 0.6 m2 Stainless Steel Filter 024 (BHS Sonthofen Inc). The slurry, having a solids concentration of 7.5-8%, was fed at 70°C at an output of 0.5-1.5 gal/min (approximately average of 1 gal/min). The washed liquid was city water at 70°C. Polypropylene (850 µm thick, air permeability 50 L/m2S) was used as a filtration material. Prior to filtration, the slurry was sparged with steam to raise the temperature to 70°C. The slurry was panned and heated in batches using steam and an air dispersion device. The slurry was then pumped into the filter using a diaphragm pump. The filter cake was washed with hot water. The filter cake was allowed to dehydrate under vacuum, and discharged, via a 90 degree roller. The cake was analyzed for moisture, ash and residual free sugars, with the results summarized in Table 11, showing effective washing and dehydration of the remaining lignocellulose stream. The clarity of the filtrate was assessed by centrifuging a sample of the filtrate. The solid content of the mother filter was estimated to be less than 0.1%, and no solid content was seen in the wash filtrate, indicating that the solids were efficiently removed by filtration. Table 11: Moisture, ash and residual sugar in the remaining stream of lignocellulose

Example 12 - Refining of hemicellulose hydrolyzate collected in Example 11

Referência: DB4 D01 Tabela 12B: Composição de açúcar de uma corrente de açúcar enriquecida com xilose produzida por extração de açúcar de hemicelulose e purificação de bagaço

Referência: DB4D02[00135] The hemicellulose hydrolyzate collected in Example 11 was refined by contact with a SAC resin, followed by amine extraction. The refined aqueous solution was evaporated to remove the solvent, then polished by contact with a SAC resin, a WBA resin, an MB resin, and finally evaporation to about 70% weight/weight DS. The final sugar products were analyzed and shown to have the compositions in Table 12A. Some of the material was fractionated by chromatography to enrich the xylose fraction, the composition of which is provided in Table 12B. Both samples were successfully fermented to Xylitol by various microorganisms, with appropriate addition of C6 sugars (eg glucose) to support microorganism proliferation. Table 12A: Sugar composition of a refined hemicellulose sugar stream produced by hemicellulose sugar extraction and bagasse purification

Reference: DB4 D01 Table 12B: Sugar composition of a xylose-enriched sugar stream produced by hemicellulose sugar extraction and bagasse purification

Reference: DB4D02

Example 13 - Biomass composition analysis after soil removal step and hemicellulose extraction step on a pilot scale

[00136] Bagasse from Raceland, LA was deashed according to Example 10, and extracted and separated as described in Example 11. Samples of solid biomass were collected after each process step, dried and analyzed for their composition. Table 13 summarizes the results, indicating efficient deashing of the solid in the ash removal step/soil removal step, and efficient extraction of hemicellulose sugars, as well as reduction of many of the remaining metal elements in the biomass by extraction of the physiologically bound metals in the extraction step. Ash-depleted biomass is anticipated to be much more suitable than feedstock biomass for use as feed to energy uses, for example, oxidative burning to produce energy directly, or pyrolysis to produce bio-oil. The hemi-depleted biomass is anticipated to be an even better feed for energy proposal, as more inorganic content is removed as well as some carbohydrates, consequently the percentage of lignin being increased from an average of ~24% to an average of ~40%. Higher lignin content and lower sugar content result in higher energy density of the biomass. Table 13: Composition analysis of Raceland bagasse after the ash removal step and after the hemicellulose extraction step

Example 14 - Fermentation of a refined hemicellulose sugar stream

[00137] A fermenter containing fermentation medium (tryptone, 14 g; yeast extract, 7 g; potassium phosphate, dibasic, 4.2 g; sodium chloride, 7 g; magnesium sulfate, 2 g; water, 750 mL, antifoam Cognis Clerol FBA 3107, 3 drops) is sterilized as described in Pub. U.S. At the. 2013/0217070. A stream of refined hemicellulose sugar prepared according to the object methods (e.g. as in Examples 5 and 7) is added (100 ml, comprising 30 g of xylose). The fermenter is inoculated with 50 ml of a starter culture of a suitable microorganism (e.g. ZUC220 or ZUC170) at 30°C, and allowed to ferment if passed at 30°C and pH 7.0 (controlled NH4OH) with agitation ( 800 RPM) and introduction of air at 1 LPM as described in Pub. U.S. At the. 2013/0217070. The volume after inoculation is 900 mL. After 24 hours, additional refined hemicellulose sugar stream is added (185 ml, comprising 130 g of xylose). The fermentation is allowed to operate for a total of 80 hours after inoculation before separating the microorganisms from the Xylitol stream by filtration. Xylitol is crystallized as described in Example 8. The fermentation methods of the disclosure can exhibit a volumetric productivity of more than 1.5 g/L/h (“A” productivity), from 1.0 to 1.5 g/h L/h (“B” productivity), from 0.5 to 1.0 g/L/h (“C” productivity), or less than 0.5 g/L/h (“D” productivity). In some examples, the yield of Xylitol from the fermentation methods described herein is greater than 100 g/L (“Yield “A”), from 75 to 100 g/L (“Yield “B”), from 50 to 75 g/L (yield “C”), or less than 50 g/L (yield “D”). Additional examples of fermentation conditions can be found, for example, in Pub. U.S. At the. 2013/0217070.

Example 15 - Protein and amino acid removal by sugar refining method

CONCRETIZAÇÕES ADICIONAIS DA INVENÇÃO 1. Um método de produção de Xilitol de uma biomassa contendo lignocelulose, compreendendo: fermentar uma corrente de açúcar de hemicelulose refinado para produzir um caldo de fermentação compreendendo Xilitol; e recuperar Xilitol a partir do caldo de fermentação; no qual a corrente de açúcar de hemicelulose refinado foi produzida por um processo compreendendo: extrair açúcares de hemicelulose da biomassa, obtendo-se, desse modo, uma corrente de açúcar de hemicelulose e uma corrente remanescente de lignocelulose; contatar a corrente de açúcar de hemicelulose com um agente de extração de amina para formar uma mistura; e separar da mistura uma corrente orgânica compreendendo o agente de extração de amina, e pelo menos uma impureza, e a corrente de açúcar de hemicelulose refinado. 2. O método, de acordo com a concretização 1, no qual a biomass é selecionada de madeira dura, polpa de madeira, bagaço, folhas de cana de açúcar, bétula, eucalipto, espigas de milho, palha de milho, cascas de amendoim, grama, e palha de trigo, ou uma combinação destes. 3. O método, de acordo com a concretização 2, no qual a biomassa é selecionada de bagaço e folhas de cana de açúcar, ou uma combinação destes. 4. O método, de acordo com qualquer uma das concreti-zações 1 a 3, compreendendo adicionalmente reduzir cinza e teor de solo da biomassa antes da extração de açúcares de hemicelulose da biomassa. 5. O método, de acordo com a concretização 4, no qual a redução compreende um ou mais estágios de formação de pasta fluida, lavagem, e desidratação da biomassa. 6. O método, de acordo com qualquer uma das concreti- zações 1 a 5, no qual a extração de açúcares de hemicelulose com-preende extração de água quente. 7. O método, de acordo com a concretização 6, compre-endendo adicionalmente um ácido. 8. O método, de acordo com a concretização 7, no qual o ácido é um ácido inorgânico. 9. O método, de acordo com a concretização 7 ou 8, no qual o ácido está presente em uma quantidade até 2% peso/peso. 10. O método, de acordo com qualquer uma das concreti-zações 6 a 9, no qual a extração ocorre à uma temperatura de 100 a 200°C. 11. O método, de acordo com qualquer uma das concreti-zações 1 a 10, no qual o agente de extração de amina compreende uma amina e um diluente. 12. O método, de acordo com a concretização 11, no qual a amina compreende pelo menos 20 átomos de carbono. 13. O método, de acordo com a concretização 12, no qual a amina é trilaurilamima. 14. O método, de acordo com qualquer uma das concreti-zações 11 a 13, no qual o diluente compreende um álcool. 15. O método, de acordo com a concretização 14, no qual o diluente compreende hexanol ou 2-etil-1-hexanol. 16. O método, de acordo com qualquer uma das concreti-zações 11 a 13, no qual o diluente compreende um C6-12 monoálcool, querosene, ou uma mistura destes. 17. O método, de acordo com qualquer uma das concreti-zações 1 a 16, no qual a pelo menos uma impureza é selecionada de cinza, lignina solúvel ácida, furfural, ácidos graxos, ácidos inorgânicos, ácidos orgânicos, metanol, proteínas, amino ácidos, glicerol, esteróis, ácido resínico, e materiais cerosos. 18. O método, de acordo com qualquer uma das concreti-zações 1 a 17, no qual o caldo de fermentação compreende adicionalmente um microrganismo selecionado de bactéria que ocorre naturalmente, bactéria recombinante, levedura que ocorre naturalmente, levedura recombinante, e fungos. 19. O método, de acordo com a concretização 18, no qual o microrganismo é uma estirpe de E. coli. 20. O método, de acordo com qualquer uma das concreti-zações 1 a 19, no qual a fermentação produz, em menos do que 80 horas, pelo menos 60 gramas do Xilitol por litro do caldo de fermentação. 21. O método, de acordo com a concretização 20, no qual a fermentação produz, em menos do que 80 horas, pelo menos 100 gramas do Xilitol por litro do caldo de fermentação. 22. O método, de acordo com qualquer uma das concreti-zações 1 a 21, no qual a fermentação produz o Xilitol a uma taxa de pelo menos 1 g/L/h. 23. O método, de acordo com qualquer uma das concreti-zações 1 a 22, no qual o caldo de fermentação compreende menos do que 1 grama de etanol por litro. 24. O método, de acordo com qualquer uma das concreti-zações 1 a 23, no qual pelo menos 70% de xilose na biomassa é con-vertido em Xilitol. 25. O método, de acordo com qualquer uma das concreti-zações 1 a 24, no qual o teor de xilose da corrente de açúcar de hemi- celulose refinado é pelo menos 80% do teor de xilose da corrente de açúcar de hemicelulose. 26. O método, de acordo com qualquer uma das concreti-zações 1 a 25, no qual a fermentação não compreende xilose purificada por cristalização. 27. O método, de acordo com qualquer uma das concreti-zações 1 a 26, no qual a corrente de açúcar de hemicelulose refinado compreende pelo menos 50% de xilose peso/peso relativo aos açúcares dissolvidos totais. 28. O método, de acordo com a concretização 27, no qual a corrente de açúcar de hemicelulose refinado compreende entre 50 e 90% de xilose peso/peso relativo aos açúcares dissolvidos totais. 29. Um método para produção de Xilitol por fermentação de uma corrente de açúcar de hemicelulose refinado derivada de um hi- drolisato lignocelulósico, compreendendo converter xilose na corrente de açúcar de hemicelulose refinado a Xilitol através da fermentação por um microrganismo, no qual a corrente de açúcar de hemicelulose refinado compreende: 50 a 90% xilose peso/peso relativo aos açúcares dissolvidos totais, menos do que 200 ppm de cálcio e furfural em uma quantidade até 1000 ppm. 30. O método, de acordo com a concretização 29, no qual o microrganismo é selecionado de bactéria que ocorre naturalmente, bactéria recombinante, levedura que ocorre naturalmente, levedura recombinante, e fungos. 31. O método, de acordo com a concretização 30, no qual o microrganismo é um estirpe de E. coli. 32. O método, de acordo com qualquer uma das concreti-zações 29 a 31, no qual a fermentação produz, em menos do que 80 horas, pelo menos 60 gramas do Xilitol por litro de caldo de fermentação. 33. O método, de acordo com qualquer uma das concreti-zações 29 a 32, no qual a fermentação produz, em menos do que 80 horas, pelo menos 100 gramas do Xilitol por litro de caldo de fermentação. 34. O método, de acordo com qualquer uma das concreti- zações 29 a 33, no qual a fermentação produz o Xilitol a uma taxa de pelo menos 1 g/L/h. 35. O método, de acordo com qualquer uma das concreti-zações 1 a 34, no qual a corrente de açúcar de hemicelulose refinado compreende menos do que 5% de oligômeros peso/peso relativo aos açúcares dissolvidos totais. 36. O método, de acordo com qualquer uma das concreti-zações 1 a 35, no qual a corrente de açúcar de hemicelulose refinado compreende arabinose em uma quantidade até 12% peso/peso relativo aos açúcares dissolvidos totais. 37. O método, de acordo com a concretização 36, no qual a corrente de açúcar de hemicelulose refinado compreende entre 3 e 12% de arabinose peso/peso relativo aos açúcares dissolvidos totais. 38. O método, de acordo com qualquer uma das concreti-zações 1 a 37, no qual a corrente de açúcar de hemicelulose refinado compreende pelo menos 10% de hexoses peso/peso relativo aos açúcares dissolvidos totais. 39. O método, de acordo com a concretização 38, no qual a corrente de açúcar de hemicelulose refinado compreende entre 10 e 50% de hexoses peso/peso relativo aos açúcares dissolvidos totais. 40. O método, de acordo com a concretização 38 ou 39, no qual as hexoses compreendem glicose, galactose, manose, e frutose. 41. O método, de acordo com qualquer uma das concreti-zações 38 a 40, no qual a glicose e frutose compreendem pelo menos 50% peso/peso das hexoses. 42. O método, de acordo com qualquer uma das concreti-zações 1 a 41, no qual a proporção de xilose para hexoses é entre 1,5:1 e 5:1 peso/peso. 43. O método, de acordo com qualquer uma das concreti-zações 1 a 42, no qual a corrente de açúcar de hemicelulose refinado compreende dissacarídeos em uma quantidade até 8% peso/peso relativo aos açúcares dissolvidos totais. 44. O método, de acordo com qualquer uma das concreti-zações 1 a 43, no qual a corrente de açúcar de hemicelulose refinado compreende cinza em uma quantidade até 0,25% peso/peso. 45. O método, de acordo com qualquer uma das concreti-zações 1 a 44, no qual a corrente de açúcar de hemicelulose refinado compreende compostos fenólicos em quantidades até 200 ppm. 46. O método, de acordo com qualquer uma das concreti-zações 1 a 45, no qual a corrente de açúcar de hemicelulose refinado compreende furfural em uma quantidade até 200 ppm. 47. O método, de acordo com qualquer uma das concreti-zações 1 a 46, no qual a corrente de açúcar de hemicelulose refinado compreende menos do que 200 ppm de cálcio. 48. O método, de acordo com qualquer uma das concreti-zações 1 a 47, no qual a corrente de açúcar de hemicelulose refinado compreende nitrogênio em uma quantidade até 1000 ppm. 49. Um sistema para produção de Xilitol de uma biomassa contendo lignocelulose, compreendendo: uma unidade de extração de hemicelulose configurada para extrair e hidrolisar hemicelulose a partir da biomassa para produzir uma corrente de açúcar de hemicelulose e uma corrente remanescente de lignocelulose; uma unidade de refino em comunicação de fluido com a unidade de extração, no qual a unidade de refino é configurada para receber a corrente de açúcar de hemicelulose e um agente de extração de amina, e no qual o agente de extração de amina remove impurezas a partir da corrente de açúcar de hemicelulose para produzir uma corrente de açúcar de hemicelulose refinado; uma unidade de detecção configurada para analisar um ou mais parâmetros da corrente de açúcar de hemicelulose refinado; uma unidade de fermentação em comunicação de fluido com a unidade de refino para receber a corrente de açúcar de hemice- lulose refinado, no qual a unidade de fermentação é configurada para conter a corrente refinada e um microorganismo, e no qual o microrganismo facilita a produção do Xilitol de um monossacarídeo na corrente refinada para produzir um caldo de fermentação; e uma unidade de refino de Xilitol, no qual a Unidade de refino de Xilitol é configurada para remover o Xilitol do caldo de fermentação. 50. O sistema, de acordo com a concretização 49, compre-endendo adicionalmente uma unidade de lavagem configurada para remover cinza e solo da biomassa, no qual a unidade de extração de hemicelulose está em comunicação de fluido com a unidade de lavagem. 51. O sistema, de acordo com a concretização 49 ou 50, no qual pelo menos 90% de xilose na corrente de açúcar de hemicelulose refinado é convertida a Xilitol na unidade de fermentação. 52. O sistema, de acordo com qualquer uma das concreti-zações 49 a 51, no qual o Xilitol é produzido a uma taxa de pelo menos 1 g/L/h na unidade de fermentação. 53. O sistema, de acordo com qualquer uma das concreti-zações 49 a 52, no qual o caldo de fermentação compreende menos do que 10 g/L de etanol. 54. O sistema, de acordo com a concretização 53, no qual o caldo de fermentação compreende menos do que 4,5 g/L de etanol. 55. O sistema, de acordo com a concretização 53, no qual o caldo de fermentação compreende menos do que 1 g/L de etanol. 56. O sistema, de acordo com qualquer uma das concreti-zações 49 a 55, no qual a biomassa é selecionada de bagaço e folhas de cana de açúcar, ou uma combinação destes. 57. O sistema, de acordo com qualquer uma das concreti-zações 49 a 56, no qual os um ou mais parâmetros são selecionados de pH, absorvência de luz, condutividade, densidade, concentração de xilose, e concentração de hexose. 58. Uma matéria-prima de fermentação compreendendo: 50 a 90% de xilose peso/peso relativo aos açúcares dissol-vidos totais; 10 a 45% de hexoses peso/peso relativo aos açúcares dis-solvidos totais; arabinose em uma quantidade até 12% peso/peso relativo aos açúcares dissolvidos totais; dissacarídeos em uma quantidade até 8% peso/peso relativo aos açúcares dissolvidos totais; furfural em uma quantidade até 1000 ppm; e menos do que 200 ppm de cálcio. 59. A matéria-prima de fermentação, de acordo com a con-cretização 58, compreendendo adicionalmente: menos do que 1000 ppm de ácido acético; e menos do que 1000 ppm de ácido fórmico. 60. A matéria-prima de fermentação, de acordo com a con-cretização 58 ou 59, compreendendo adicionalmente um C6-12 monoál- cool em uma quantidade até 100 ppm. 61. A matéria-prima de fermentação, de acordo com qualquer uma das concretizações 58 a 60, compreendendo adicionalmente nitrogênio em uma quantidade até 1000 ppm. 62. A matéria-prima de fermentação, de acordo com qualquer uma das concretizações 58 a 61, compreendendo adicionalmente um microrganismo. 63. Um caldo de fermentação compreendendo: pelo menos 60 g/L de Xilitol menos do que 10 g/L de etanol; xilose em uma quantidade até 50 g/L; hexoses em uma quantidade até 35 g/L; furfural em uma quantidade até 1000 ppm; e menos do que 200 ppm de cálcio. 64. O caldo de fermentação, de acordo com a concretização 63, compreendendo adicionalmente: menos do que 1000 ppm de ácido acético; e menos do que 1000 ppm de ácido fórmico. 65. O caldo de fermentação, de acordo com a concretização 63 ou 64, compreendendo adicionalmente um C6-12 monoálcool em uma quantidade até 100 ppm. 66. O caldo de fermentação, de acordo com qualquer uma das concretizações 63 a 65, compreendendo adicionalmente um mi-crorganismo. 67. Uma composição de Xilitol compreendendo: pelo menos 98% de Xilitol peso/peso relativo aos sólidos dissolvidos totais; oligossacarídeos em uma quantidade até 1% peso/peso re-lativo aos sólidos dissolvidos totais; e hexoses em uma quantidade até 1%. 68. A composição, de acordo com a concretização 67, compreendendo adicionalmente cinza em uma quantidade até 0,25% peso/peso relativo aos sólidos dissolvidos totais. 69. A composição, de acordo com a concretização 67 ou 68, compreendendo adicionalmente furfural em uma quantidade até 1000 ppm. 70. A composição, de acordo com qualquer uma das con-cretizações 67 a 69, compreendendo adicionalmente uma amina em uma quantidade até 100 ppm, e no qual a amina compreende pelo menos 12 átomos de carbono. 71. A composição, de acordo com qualquer uma das con-cretizações 67 a 70, compreendendo adicionalmente um C6-12 monoál- cool em uma quantidade até 100 ppm. 72. A composição, de acordo com qualquer uma das con-cretizações 67 a 71, no qual as hexoses são selecionadas de glicose, galactose, manose, e frutose. 73. A composição, de acordo com qualquer uma das con-cretizações 67 a 72, compreendendo adicionalmente menos do que 100 ppm de arabitol. 74. A composição, de acordo com qualquer uma das con-cretizações 67 a 73, compreendendo adicionalmente menos do que 100 ppm de galactitol. 75. A composição, de acordo com a reivindicação 74, com-preendendo adicionalmente menos do que 1 ppm de galactitol. 76. A composição, de acordo com qualquer uma das con-cretizações 67 a 75, no qual a composição é derivada de um hidrolisa- to de uma biomassa contendo lignocelulose. 77. A composição, de acordo com qualquer uma das con-cretizações 67 a 76, no qual a composição é cristalina. 78. A composição, de acordo com qualquer uma das con-cretizações 67 a 76, no qual a composição é provida como uma solução aquosa. 79. A composição, de acordo com a concretização 78, no qual a solução aquosa compreende pelo menos 50% peso/peso de sólidos dissolvidos. 80. Um método de produção de uma corrente de açúcar de hemicelulose refinado adequada para conversão a Xilitol, compreendendo: extrair açúcares de hemicelulose a partir da biomassa, ob-tendo-se, desse modo, uma corrente de açúcar de hemicelulose e uma corrente remanescente de lignocelulose; contatar a corrente de açúcar de hemicelulose com um agente de extração de amina para formar uma mistura; separar da mistura uma corrente orgânica compreendendo o agente de extração de amina, e pelo menos uma impureza e uma corrente de açúcar de hemicelulose refinado; e medir as concentrações de pelo menos uma de xilose, ara-binose, hexoses, dissacarídeos, cinza, ácido acético, ácido fórmico, compostos fenólicos, furfural, cálcio, e nitrogênio; no qual a corrente de açúcar de hemicelulose refinado é adequada para conversão a Xilitol se a corrente refinada compreende: pelo menos 50% de xilose peso/peso relativo aos açúcares dissolvidos totais; pelo menos 10% de hexoses peso/peso relativo aos açúcares dissolvidos totais; e menos do que 200 ppm de cálcio; e no qual a corrente refinada adequada para conversão a Xilitol compreende adicionalmente pelo menos uma característica selecionada de: arabinose em uma quantidade até 12% peso/peso relativo aos açúcares dissolvidos totais; dissacarídeos em uma quantidade até 8% peso/peso relativo aos açúcares dissolvidos totais; cinza em uma quantidade até 0,25% peso/peso; menos do que 1000 ppm de ácido acético; menos do que 1000 ppm de ácido fórmico; compostos fenólicos em uma quantidade até 200 ppm; furfural em uma quantidade até 200 ppm; e nitrogênio em uma quantidade até 1000 ppm; e no qual uma corrente refinada inadequada para conversão a Xilitol é adicionalmente refinada. 81. O método, de acordo com a concretização 80, no qual a corrente refinada adequada para conversão a Xilitol compreende adi-cionalmente furfural em uma quantidade até 200 ppm. 82. O método, de acordo com a concretização 80 ou 81, no qual a corrente refinada adequada para conversão a Xilitol compreende adicionalmente arabinose em uma quantidade até 12% peso/peso relativo aos açúcares dissolvidos totais. 83. O método, de acordo com qualquer uma das concreti-zações 80 a 82, no qual a corrente refinada adequada para conversão a Xilitol compreende adicionalmente dissacarídeos em uma quantidade até 8% peso/peso relativo aos açúcares dissolvidos totais. 84. O método, de acordo com qualquer uma das concreti-zações 80 a 83, no qual a corrente refinada adequada para conversão a Xilitol compreende adicionalmente cinza em uma quantidade até 0,25% peso/peso. 85. O método, de acordo com qualquer uma das concreti-zações 80 a 84, no qual a corrente refinada adequada para conversão a Xilitol compreende adicionalmente ácido acético em uma quantidade até 1000 ppm. 86. O método, de acordo com qualquer uma das concreti-zações 80 a 85, no qual a corrente refinada adequada para conversão a Xilitol compreende adicionalmente ácido fórmico em uma quantidade até 1000 ppm. 87. O método, de acordo com qualquer uma das concreti-zações 80 a 86, no qual a corrente refinada adequada para conversão a Xilitol compreende adicionalmente compostos fenólicos em uma quantidade até 200 ppm. 88. O método, de acordo com qualquer uma das concreti-zações 80 a 87, no qual a corrente refinada adequada para conversão a xilitol compreende adicionalmente nitrogênio em uma quantidade até 1000 ppm.[00138] Protein and amino acids are usually present in the raw material of biomass, and can be removed from sugar solutions to avoid inhibition of some microorganisms used for industrial fermentation processes. This may be necessary when sugar cane leaves are used as a raw material, as inherently more protein and amino acids are present in the leaves than in the cane. Samples of bagasse and leaves were hydrolyzed and refined as described in Example 5. Samples of bagasse, leaves, and refined hemicellulose sugar streams derived therefrom were analyzed by Galbraith Laboratories, Inc. for nitrogen and protein content, with the results summarized in Table 15. It can be seen that nitrogen-containing molecules were efficiently removed in the refining process, as both samples comprise less than 200 ppm of nitrogen. Table 15: Nitrogen and protein analysis in biomass and refined hemicellulose sugar streams produced therefrom

FURTHER EMBODIMENTS OF THE INVENTION 1. A method of producing Xylitol from a lignocellulose-containing biomass, comprising: fermenting a refined hemicellulose sugar stream to produce a fermentation broth comprising Xylitol; and recovering Xylitol from the fermentation broth; wherein the refined hemicellulose sugar stream was produced by a process comprising: extracting hemicellulose sugars from the biomass, thereby obtaining a hemicellulose sugar stream and a lignocellulose remnant stream; contacting the hemicellulose sugar stream with an amine extracting agent to form a mixture; and separating from the mixture an organic stream comprising the amine extracting agent, and at least one impurity, and the refined hemicellulose sugar stream. 2. The method according to embodiment 1, in which the biomass is selected from hardwood, wood pulp, bagasse, sugar cane leaves, birch, eucalyptus, corn cobs, corn straw, peanut shells, grass, and wheat straw, or a combination thereof. 3. The method, according to embodiment 2, in which the biomass is selected from sugar cane bagasse and leaves, or a combination thereof. 4. The method according to any one of embodiments 1 to 3, further comprising reducing ash and soil content of the biomass prior to extracting hemicellulose sugars from the biomass. 5. The method according to embodiment 4, in which the reduction comprises one or more stages of slurrying, washing, and dewatering the biomass. 6. The method according to any one of embodiments 1 to 5, in which extracting sugars from hemicellulose comprises hot water extraction. 7. The method according to embodiment 6 further comprising an acid. 8. The method according to embodiment 7, in which the acid is an inorganic acid. 9. The method according to embodiment 7 or 8, in which the acid is present in an amount of up to 2% weight/weight. 10. The method according to any one of embodiments 6 to 9, in which the extraction takes place at a temperature of 100 to 200°C. 11. The method according to any one of embodiments 1 to 10, in which the amine extracting agent comprises an amine and a diluent. 12. The method according to embodiment 11, in which the amine comprises at least 20 carbon atoms. 13. The method according to embodiment 12, in which the amine is trilaurylamine. 14. The method according to any one of embodiments 11 to 13, in which the diluent comprises an alcohol. 15. The method according to embodiment 14, wherein the diluent comprises hexanol or 2-ethyl-1-hexanol. 16. The method according to any one of embodiments 11 to 13, in which the diluent comprises a C6-12 monoalcohol, kerosene, or a mixture thereof. 17. The method according to any one of embodiments 1 to 16, in which the at least one impurity is selected from ash, acid soluble lignin, furfural, fatty acids, inorganic acids, organic acids, methanol, proteins, amino acids, glycerol, sterols, resin acid, and waxy materials. 18. The method according to any one of embodiments 1 to 17, in which the fermentation broth further comprises a microorganism selected from naturally occurring bacteria, recombinant bacteria, naturally occurring yeast, recombinant yeast, and fungi. 19. The method according to embodiment 18, in which the microorganism is a strain of E. coli. 20. The method according to any one of embodiments 1 to 19, in which the fermentation produces, in less than 80 hours, at least 60 grams of the Xylitol per liter of the fermentation broth. 21. The method according to embodiment 20, in which the fermentation produces, in less than 80 hours, at least 100 grams of the Xylitol per liter of the fermentation broth. 22. The method according to any one of embodiments 1 to 21, in which fermentation produces Xylitol at a rate of at least 1 g/L/hr. 23. The method according to any one of embodiments 1 to 22, in which the fermentation broth comprises less than 1 gram of ethanol per liter. 24. The method according to any one of embodiments 1 to 23, in which at least 70% of the xylose in the biomass is converted to Xylitol. 25. The method according to any one of embodiments 1 to 24, in which the xylose content of the refined hemicellulose sugar stream is at least 80% of the xylose content of the hemicellulose sugar stream. 26. The method according to any one of embodiments 1 to 25, in which the fermentation does not comprise xylose purified by crystallization. 27. The method according to any one of embodiments 1 to 26, wherein the refined hemicellulose sugar stream comprises at least 50% xylose weight/weight relative to total dissolved sugars. 28. The method according to embodiment 27, wherein the refined hemicellulose sugar stream comprises between 50 and 90% xylose weight/weight relative to total dissolved sugars. 29. A method for producing Xylitol by fermenting a refined hemicellulose sugar stream derived from a lignocellulosic hydrolyzate, comprising converting xylose in the refined hemicellulose sugar stream to Xylitol through fermentation by a microorganism, in which the refined hemicellulose sugar stream Refined hemicellulose sugar comprises: 50 to 90% xylose weight/weight relative to total dissolved sugars, less than 200 ppm calcium and furfural in an amount up to 1000 ppm. 30. The method according to embodiment 29, in which the microorganism is selected from naturally occurring bacteria, recombinant bacteria, naturally occurring yeast, recombinant yeast, and fungi. 31. The method according to embodiment 30, in which the microorganism is a strain of E. coli. 32. The method according to any one of embodiments 29 to 31, in which the fermentation produces, in less than 80 hours, at least 60 grams of the Xylitol per liter of fermentation broth. 33. The method according to any one of embodiments 29 to 32, in which the fermentation produces, in less than 80 hours, at least 100 grams of the Xylitol per liter of fermentation broth. 34. The method according to any one of embodiments 29 to 33, in which fermentation produces Xylitol at a rate of at least 1 g/L/hr. 35. The method according to any one of embodiments 1 to 34, wherein the refined hemicellulose sugar stream comprises less than 5% weight/weight oligomers relative to total dissolved sugars. 36. The method according to any one of embodiments 1 to 35, in which the refined hemicellulose sugar stream comprises arabinose in an amount of up to 12% weight/weight relative to the total dissolved sugars. 37. The method according to embodiment 36, wherein the refined hemicellulose sugar stream comprises between 3 and 12% arabinose weight/weight relative to total dissolved sugars. 38. The method according to any one of embodiments 1 to 37, wherein the refined hemicellulose sugar stream comprises at least 10% weight/weight hexoses relative to total dissolved sugars. 39. The method according to embodiment 38, wherein the refined hemicellulose sugar stream comprises between 10 and 50% weight/weight hexoses relative to total dissolved sugars. 40. The method according to embodiment 38 or 39, wherein the hexoses comprise glucose, galactose, mannose, and fructose. 41. The method according to any one of embodiments 38 to 40, in which the glucose and fructose comprise at least 50% weight/weight of the hexoses. 42. The method according to any one of embodiments 1 to 41, in which the ratio of xylose to hexoses is between 1.5:1 and 5:1 weight/weight. 43. The method according to any one of embodiments 1 to 42, in which the refined hemicellulose sugar stream comprises disaccharides in an amount of up to 8% weight/weight relative to the total dissolved sugars. 44. The method according to any one of embodiments 1 to 43, in which the refined hemicellulose sugar stream comprises ash in an amount of up to 0.25% weight/weight. 45. The method according to any one of embodiments 1 to 44, wherein the refined hemicellulose sugar stream comprises phenolic compounds in amounts up to 200 ppm. 46. The method according to any one of embodiments 1 to 45, in which the refined hemicellulose sugar stream comprises furfural in an amount up to 200 ppm. 47. The method according to any one of embodiments 1 to 46, wherein the refined hemicellulose sugar stream comprises less than 200 ppm of calcium. 48. The method according to any one of embodiments 1 to 47, in which the refined hemicellulose sugar stream comprises nitrogen in an amount up to 1000 ppm. 49. A system for producing Xylitol from a lignocellulose-containing biomass, comprising: a hemicellulose extraction unit configured to extract and hydrolyze hemicellulose from the biomass to produce a hemicellulose sugar stream and a lignocellulose remnant stream; a refining unit in fluid communication with the extraction unit, in which the refining unit is configured to receive the hemicellulose sugar stream and an amine extracting agent, and in which the amine extracting agent removes impurities from starting from the hemicellulose sugar stream to produce a refined hemicellulose sugar stream; a detection unit configured to analyze one or more parameters of the refined hemicellulose sugar stream; a fermentation unit in fluid communication with the refining unit to receive the refined hemicellulose sugar stream, in which the fermentation unit is configured to contain the refined stream and a microorganism, and in which the microorganism facilitates production of Xylitol from a monosaccharide in the refined stream to produce a fermentation broth; and a Xylitol Refining Unit, in which the Xylitol Refining Unit is configured to remove Xylitol from the fermentation broth. 50. The system according to embodiment 49 further comprising a scrubbing unit configured to remove ash and soil from biomass, in which the hemicellulose extraction unit is in fluid communication with the scrubbing unit. 51. The system according to embodiment 49 or 50, in which at least 90% of the xylose in the refined hemicellulose sugar stream is converted to Xylitol in the fermentation unit. 52. The system according to any one of embodiments 49 to 51 in which Xylitol is produced at a rate of at least 1 g/L/h in the fermentation unit. 53. The system according to any one of embodiments 49 to 52, in which the fermentation broth comprises less than 10 g/L of ethanol. 54. The system according to embodiment 53, in which the fermentation broth comprises less than 4.5 g/L of ethanol. 55. The system according to embodiment 53, in which the fermentation broth comprises less than 1 g/L of ethanol. 56. The system according to any one of embodiments 49 to 55, in which the biomass is selected from sugar cane bagasse and leaves, or a combination thereof. 57. The system according to any one of embodiments 49 to 56, in which the one or more parameters are selected from pH, light absorbance, conductivity, density, xylose concentration, and hexose concentration. 58. A fermentation raw material comprising: 50 to 90% xylose weight/weight relative to total dissolved sugars; 10 to 45% of hexoses weight/weight relative to total dissolved sugars; arabinose in an amount of up to 12% weight/weight relative to total dissolved sugars; disaccharides in an amount of up to 8% weight/weight relative to total dissolved sugars; furfural in an amount up to 1000 ppm; and less than 200 ppm of calcium. 59. The fermentation feedstock according to embodiment 58, further comprising: less than 1000 ppm of acetic acid; and less than 1000 ppm formic acid. 60. The fermentation feedstock, according to embodiment 58 or 59, further comprising a C6-12 monoalcohol in an amount up to 100 ppm. 61. The fermentation feedstock according to any one of embodiments 58 to 60, further comprising nitrogen in an amount up to 1000 ppm. 62. The fermentation feedstock according to any one of embodiments 58 to 61, further comprising a microorganism. 63. A fermentation broth comprising: at least 60 g/L of Xylitol less than 10 g/L of ethanol; xylose in an amount up to 50 g/L; hexoses in an amount up to 35 g/L; furfural in an amount up to 1000 ppm; and less than 200 ppm of calcium. 64. The fermentation broth according to embodiment 63, further comprising: less than 1000 ppm acetic acid; and less than 1000 ppm formic acid. 65. The fermentation broth, according to embodiment 63 or 64, further comprising a C6-12 monoalcohol in an amount up to 100 ppm. 66. The fermentation broth according to any one of embodiments 63 to 65, further comprising a microorganism. 67. A Xylitol composition comprising: at least 98% Xylitol weight/weight relative to total dissolved solids; oligosaccharides in an amount up to 1% weight/weight relative to total dissolved solids; and hexoses in an amount up to 1%. 68. The composition according to embodiment 67, further comprising ash in an amount up to 0.25% weight/weight relative to total dissolved solids. 69. The composition according to embodiment 67 or 68 further comprising furfural in an amount up to 1000 ppm. 70. The composition according to any one of embodiments 67 to 69, further comprising an amine in an amount up to 100 ppm, and wherein the amine comprises at least 12 carbon atoms. 71. The composition according to any one of embodiments 67 to 70, further comprising a C6-12 monoalcohol in an amount up to 100 ppm. 72. The composition according to any one of embodiments 67 to 71, in which the hexoses are selected from glucose, galactose, mannose, and fructose. 73. The composition according to any one of embodiments 67 to 72, further comprising less than 100 ppm of arabitol. 74. The composition according to any one of embodiments 67 to 73, further comprising less than 100 ppm of galactitol. The composition of claim 74, further comprising less than 1 ppm of galactitol. 76. The composition according to any one of embodiments 67 to 75, wherein the composition is derived from a hydrolyzate of a lignocellulose-containing biomass. 77. The composition according to any one of embodiments 67 to 76, wherein the composition is crystalline. 78. The composition according to any one of embodiments 67 to 76, wherein the composition is provided as an aqueous solution. 79. The composition according to embodiment 78, wherein the aqueous solution comprises at least 50% weight/weight dissolved solids. 80. A method of producing a refined hemicellulose sugar stream suitable for conversion to Xylitol, comprising: extracting hemicellulose sugars from biomass, thereby obtaining a hemicellulose sugar stream and a residual stream of lignocellulose; contacting the hemicellulose sugar stream with an amine extracting agent to form a mixture; separating from the mixture an organic stream comprising the amine extracting agent, and at least one impurity and a refined hemicellulose sugar stream; and measuring the concentrations of at least one of xylose, ara-binose, hexoses, disaccharides, ash, acetic acid, formic acid, phenolic compounds, furfural, calcium, and nitrogen; wherein the refined hemicellulose sugar stream is suitable for conversion to Xylitol if the refined stream comprises: at least 50% xylose weight/weight relative to total dissolved sugars; at least 10% weight/weight hexoses relative to total dissolved sugars; and less than 200 ppm calcium; and wherein the refined stream suitable for conversion to Xylitol further comprises at least one feature selected from: arabinose in an amount of up to 12% weight/weight relative to total dissolved sugars; disaccharides in an amount of up to 8% weight/weight relative to total dissolved sugars; ash in an amount up to 0.25% weight/weight; less than 1000 ppm acetic acid; less than 1000 ppm formic acid; phenolic compounds in an amount up to 200 ppm; furfural in an amount up to 200 ppm; and nitrogen in an amount up to 1000 ppm; and in which a refined stream unsuitable for conversion to Xylitol is further refined. 81. The method according to embodiment 80, wherein the refined stream suitable for conversion to Xylitol further comprises furfural in an amount up to 200 ppm. 82. The method according to embodiment 80 or 81, in which the refined stream suitable for conversion to Xylitol further comprises arabinose in an amount of up to 12% weight/weight relative to the total dissolved sugars. 83. The method according to any one of embodiments 80 to 82, in which the refined stream suitable for conversion to Xylitol further comprises disaccharides in an amount up to 8% weight/weight relative to the total dissolved sugars. 84. The method according to any one of embodiments 80 to 83, wherein the refined stream suitable for conversion to Xylitol further comprises ash in an amount of up to 0.25% weight/weight. 85. The method according to any one of embodiments 80 to 84, wherein the refined stream suitable for conversion to Xylitol further comprises acetic acid in an amount up to 1000 ppm. 86. The method according to any one of embodiments 80 to 85, wherein the refined stream suitable for conversion to Xylitol further comprises formic acid in an amount up to 1000 ppm. 87. The method according to any one of embodiments 80 to 86, in which the refined stream suitable for conversion to Xylitol further comprises phenolic compounds in an amount up to 200 ppm. 88. The method according to any one of embodiments 80 to 87, in which the refined stream suitable for conversion to xylitol further comprises nitrogen in an amount up to 1000 ppm.

Claims (25)

1. Method for producing xylitol by fermenting a refined hemicellulose sugar stream derived from a lignocellulosic hydrolysate, comprising converting xylose in the refined hemicellulose sugar stream to xylitol through fermentation by a microorganism, characterized in that the refined hemicellulose sugar stream comprises: 50 to 90% xylose weight/weight relative to total dissolved sugars, at least 10% hexoses weight/weight relative to total dissolved sugars, in which glucose and fructose comprise at least 50 % weight/weight of hexoses, less than 200 ppm of calcium and furfural in an amount up to 1000 ppm. 2. Method according to claim 1, characterized in that the hexoses comprise glucose, galactose, mannose and fructose. 3. Method, according to claim 1, characterized by the fact that the ratio of xylose to hexoses is between 1.5:1 and 5:1 weight/weight. 4. Method, according to claim 1, characterized in that the stream of refined hemicellulose sugar additionally comprises arabinose in an amount up to 12% weight/weight relative to the total dissolved sugars. 5. Method, according to claim 1, characterized by the fact that the stream of refined hemicellulose sugar additionally comprises less than 5% of oligomers weight/weight relative to the total dissolved sugars. 6. Method according to claim 1, characterized in that the refined hemicellulose sugar stream additionally comprises ash in an amount of up to 0.25% weight/weight. 7. Method according to claim 1, characterized in that the stream of refined hemicellulose sugar additionally comprises phenolic compounds in amounts up to 200 ppm. 8. Method according to claim 1, characterized in that the refined hemicellulose sugar stream additionally comprises furfural in an amount of up to 200 ppm. 9. Method according to claim 1, characterized in that the stream of refined hemicellulose sugar additionally comprises nitrogen in an amount up to 1000 ppm. 10. Method, according to claim 1, characterized by the fact that the xylose has not been purified by crystallization. 11. Method, according to claim 1, characterized by the fact that the conversion produces, in less than 80 hours, at least 60 grams of xylitol per liter of fermentation broth. 12. Method according to claim 1, characterized in that the conversion produces xylitol at a rate of at least 1 g/L/h. 13. Method according to claim 1, characterized in that the conversion produces less than 1 gram of ethanol per liter of fermentation broth. 14. Fermentation raw material derived from a lignocellulosic hydrolyzate, characterized by the fact that it comprises: (i) 50 to 90% xylose weight/weight relative to total dissolved sugars; (ii) at least 10% weight/weight hexoses relative to total dissolved sugars, wherein glucose and fructose comprise at least 50% weight/weight of the hexoses; (iii) less than 200 ppm calcium; (iv) furfural in an amount up to 1000 ppm; and (v) a microorganism. 15. Fermentation raw material, according to claim 14, characterized in that it additionally comprises 10 to 50% of hexoses weight/weight relative to total dissolved sugars. 16. Fermentation raw material, according to claim 14, characterized in that it additionally comprises arabinose in an amount up to 12% weight/weight relative to total dissolved sugars. 17. Fermentation raw material, according to claim 14, characterized in that it additionally comprises disaccharides in an amount up to 8% weight/weight relative to total dissolved sugars. 18. Fermentation raw material, according to claim 14, characterized in that it additionally comprises less than 1000 ppm of acetic acid. 19. Fermentation raw material, according to claim 14, characterized in that it additionally comprises less than 1000 ppm of formic acid. 20. Fermentation raw material, according to claim 14, characterized in that it additionally comprises a C6-12 monoalcohol in an amount up to 100 ppm. 21. Fermentation raw material, according to claim 14, characterized by the fact that it additionally comprises nitrogen in an amount up to 1000 ppm. 22. Method according to claim 1, characterized in that it further comprises: (i) extracting hemicellulose sugars from the biomass containing lignocellulose, thereby obtaining a stream of hemicellulose sugar, and a remaining stream of lignocellulose ; (ii) contacting the hemicellulose sugar stream with an amine extracting agent to form a mixture; (iii) separating from the mixture an organic stream comprising the amine extracting agent, and at least one impurity and the refined hemicellulose sugar stream; (a) 50 to 90% xylose weight/weight relative to total dissolved sugars; (b) at least 10% weight/weight hexoses relative to total dissolved sugars, wherein glucose and fructose comprise at least 50% weight/weight of the hexoses; (c) less than 200 ppm of calcium, and (d) furfural in an amount of up to 1000 ppm; (iv) fermenting the refined hemicellulose sugar stream to produce a fermentation broth comprising xylitol; and (v) recovering xylitol from the fermentation broth. 23. Method according to claim 22, characterized in that at least 70% of xylose in the biomass is converted to xylitol. 24. Method according to claim 22. characterized by the fact that it comprises the reduction of the ash and soil content of the biomass before the extraction of hemicellulose sugars from the biomass, where the reduction comprises one or more stages selected from the group consisting of formation slurry, washing, dewatering, hot water extraction. 25. Fermentation raw material according to claim 14, characterized in that the fermentation raw material comprises between 0.5% and 8% of disaccharides weight/weight relative to total dissolved sugars

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