Classifications

• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P7/00—Preparation of oxygen-containing organic compounds
  • C12P7/02—Preparation of oxygen-containing organic compounds containing a hydroxy group
  • C12P7/04—Preparation of oxygen-containing organic compounds containing a hydroxy group acyclic
  • C12P7/06—Ethanol, i.e. non-beverage
  • C12P7/08—Ethanol, i.e. non-beverage produced as by-product or from waste or cellulosic material substrate
  • C12P7/10—Ethanol, i.e. non-beverage produced as by-product or from waste or cellulosic material substrate substrate containing cellulosic material
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P19/00—Preparation of compounds containing saccharide radicals
  • C12P19/02—Monosaccharides
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P19/00—Preparation of compounds containing saccharide radicals
  • C12P19/14—Preparation of compounds containing saccharide radicals produced by the action of a carbohydrase (EC 3.2.x), e.g. by alpha-amylase, e.g. by cellulase, hemicellulase
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P7/00—Preparation of oxygen-containing organic compounds
  • C12P7/02—Preparation of oxygen-containing organic compounds containing a hydroxy group
  • C12P7/04—Preparation of oxygen-containing organic compounds containing a hydroxy group acyclic
  • C12P7/06—Ethanol, i.e. non-beverage
  • C12P7/14—Multiple stages of fermentation; Multiple types of microorganisms or re-use of microorganisms
• • C—CHEMISTRY; METALLURGY
  • C13—SUGAR INDUSTRY
  • C13K—SACCHARIDES OBTAINED FROM NATURAL SOURCES OR BY HYDROLYSIS OF NATURALLY OCCURRING DISACCHARIDES, OLIGOSACCHARIDES OR POLYSACCHARIDES
  • C13K1/00—Glucose; Glucose-containing syrups
  • C13K1/02—Glucose; Glucose-containing syrups obtained by saccharification of cellulosic materials
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P2201/00—Pretreatment of cellulosic or lignocellulosic material for subsequent enzymatic treatment or hydrolysis
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P2203/00—Fermentation products obtained from optionally pretreated or hydrolyzed cellulosic or lignocellulosic material as the carbon source
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E50/00—Technologies for the production of fuel of non-fossil origin
  • Y02E50/10—Biofuels, e.g. bio-diesel
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/50—Improvements relating to the production of bulk chemicals
  • Y02P20/582—Recycling of unreacted starting or intermediate materials

Definitions

• the present invention is part of the processes for producing so-called "second generation" solutions of sugars and alcohols from lignocellulosic biomass. It relates more particularly to a process for producing a solution of sugars and ethanol.
• Lignocellulosic biomass is composed of three main components: cellulose (35 to 50%), hemicellulose (23 to 32%) which is a polysaccharide essentially consisting of pentoses and hexoses and lignin (15 to 25%). which is a macromolecule of complex structure and high molecular weight, derived from the copolymerization of phenylpropenoic alcohols. These different molecules are responsible for the intrinsic properties of the plant wall and are organized in a complex entanglement.
• Cellulose the majority of this biomass, is thus the most abundant polymer on Earth and the one with the greatest potential for forming materials and biofuels.
• the potential of cellulose and its derivatives has not, for the moment, been fully exploited, mainly because of the difficulty of extracting cellulose. Indeed, this step is made difficult by the very structure of the plants.
• the technological barriers identified in the extraction and processing of cellulose include its accessibility, its crystallinity, its degree of polymerization, the presence of hemicellulose and lignin.
• the principle of the process of converting lignocellulosic biomass by biotechnological methods uses a step of enzymatic hydrolysis of the cellulose contained in plant material to produce glucose.
• the glucose obtained can then be fermented into various products such as alcohols (ethanol, 1,3-propanediol, 1-butanol, 1,4-butanediol, etc.) or acids (acetic acid, lactic acid, 3- hydroxypropionic acid, fumaric acid, succinic acid, etc.).
• alcohols ethanol, 1,3-propanediol, 1-butanol, 1,4-butanediol, etc.
• acids acetic acid, lactic acid, 3- hydroxypropionic acid, fumaric acid, succinic acid, etc.
• Cellulose and possibly hemicelluloses are targets for enzymatic hydrolysis but are not directly accessible to enzymes. This is the reason why these substrates must undergo a pretreatment preceding the enzymatic hydrolysis step.
• the purpose of the pretreatment is to modify the physical and physicochemical properties of the lignocellulosic material, with a view to improving the accessibility of the cellulose trapped within the lignin and hemicellulose matrix.
• enzymatic hydrolysis is then carried out on the pretreated substrate. It is performed using enzymes produced by a microorganism.
• the enzymatic solution added to the pretreated substrate contains enzymes that break down cellulose into sugar solutions containing in particular glucose.
• the hydrolysis yield of cellulose and hemicelluloses is dependent on the conditions of implementation and in particular the amount of enzymatic solution added. This dependence is not linear. Indeed, a portion of the sugar polymers is easily hydrolysable following pretreatment. As a result, a low dose of enzymes will make it possible to obtain a better valorization of the expensive enzymatic solution (kg of hydrolysed sugars per kg of solution used). Nevertheless, this is to the detriment of the hydrolysis yield of the sugar polymers. It is important to note that the cost of the initial biomass is also significant in the cost price of the final product. Conversely, maximum hydrolysis of the substrate will require a very large dose of enzymes. It should be noted that certain pretreatments and / or substrates produce pretreated solids containing so-called recalcitrant cellulose that is difficult to fully hydrolyze.
• the sugars produced by the enzymatic hydrolysis are then converted by fermentation into alcohols.
• an effluent containing a liquid fraction, containing (s) alcohol (s) and unfermented sugars, and a solid residue still containing polymers of sugars, in quantity, are obtained. more or less important depending on the performance of enzymatic hydrolysis.
• the present invention more particularly proposes a recovery of the solid residues obtained at the end of the hydrolysis and fermentation steps, with a view to improving the overall mass balance and therefore the economic viability of the process, in particular on the refractory substrates. It also allows by recycling solutions containing enzymes, and sugars and / or alcohol (s) produced in the various stages of the process, to benefit from the residual enzyme activity and to obtain a solution of sugars and / or alcohol more concentrated at the end of the process.
• a process for converting lignocellulosic biomass into fermentable sugars with excellent yields has been described in applications FR2963008, FR2963009 and FR1 1/02730 of the applicant.
• This process involves the firing of biomass in hydrated, inexpensive, widely available and recyclable inorganic salts.
• This technology is simple to implement and makes it easy to envisage an extrapolation at the industrial level.
• the cellulose resulting from this treatment is very reactive in enzymatic hydrolysis.
• compositional analyzes carried out on the solid fraction resulting from this pretreatment show that the hemicellulose contained in the biomass is partially hydrolysed during cooking.
• the products resulting from this hydrolysis are thus found in the liquid fraction consisting of the anti-solvent and the hydrated inorganic salt.
• the recovery of these hydrolysis products of hemicellulose proves difficult because of the high salt concentration of this solution and requires a complex and expensive process.
• the recycling of the inorganic salt is made more complex and requires a high purge rate in order to limit the accumulation of hemicellulose hydrolysis products during recycling.
• the firing in the hydrated inorganic salts will therefore advantageously be carried out on the solid residue of the hydrolysis and fermentation stages, depleted in hemicelluloses.
• the use of the solid residue relative to the native biomass in the salt treatment thus makes it easier to recycle the salt.
• the object of the present invention is to provide a method of complementary treatment of the solid residue obtained after the hydrolysis and fermentation steps for optimized recovery of the initial resource.
• the complementary treatment method according to the invention is a treatment with hydrated inorganic salts.
• the present invention describes a process for producing solutions of sugars and alcohols from lignocellulosic biomass comprising the following steps: a) pretreatment of a feedstock comprising lignocellulosic biomass,
• step b) enzymatically hydrolyzing the pretreated and optionally washed feed from step a) using cellulolytic and / or hemicellulolytic enzymes producing an effluent comprising a hydrolyzate containing sugars and a solid residue,
• step b) an alcoholic fermentation of the hydrolyzate contained in the effluent from step b) in alcohol is carried out by an alcoholic microorganism so as to produce a fermented effluent containing alcohol,
• step d) a step is carried out for extracting the alcohol from the fermented effluent from step c), e) a step is carried out for separating the effluent obtained either at the end of step c) or at the end of step d) so as to produce a solid residue and a liquid fraction,
• step f) optionally carrying out a washing step and optionally a drying step of the solid residue obtained in step e),
• a step is carried out for cooking the solid residue obtained in step e) and / or f) in a medium comprising at least one hydrated inorganic salt of formula MX n .n'H 2 0, in which M is a metal chosen from groups 1 to 13 of the periodic table, X is an anion and n is an integer between 1 and 6 and n 'is between 0.5 and 12, making it possible to obtain a solid fraction and a liquid fraction.
• step h) a step of treatment of said solid fraction obtained in step h) is carried out
• step j) performing either a step of enzymatic hydrolysis of said solid fraction obtained in step h) and / or i), or steps of enzymatic hydrolysis and alcoholic fermentation of said solid fraction obtained in step h) and yes).
• the process according to the present invention makes it possible to effectively convert various types of native lignocellulosic biomass into alcohol (s) and into one or more sugar solutions, with optimal extraction of the cellulose fraction. It also has the advantage of using inexpensive reagents, widely available and recyclable, thus obtaining a low additional processing cost. This technology is also simple to implement and makes it easy to envisage an extrapolation at the industrial level.
• Alcohols and / or sugars are thus obtained by the process according to the invention by steps d), e), j) and optionally f).
• a solution of sugars resulting from hemicellulose obtained after step a) is obtained if an acid pretreatment or without addition of chemical reagents is performed, supplemented with a solid / liquid separation and possibly a wash before step b).
• the lignocellulosic biomass, or lignocellulosic materials used in the process according to the invention is obtained from wood (hardwood and softwood), raw or treated, by agricultural products such as straw, plant fibers, cultures. forestry, residues of alcoholic, sugar and cereal plants, residues of the paper industry, marine biomass (eg, cellulosic macroalgae) or transformation products of cellulosic or lignocellulosic materials.
• the lignocellulosic materials can also be biopolymers and are preferably rich in cellulose.
• the lignocellulosic biomass used is wood, wheat straw, wood pulp, miscanthus, rice straw or corn stalks.
• the different types of lignocellulosic biomass can be used alone or in mixture.
• the pretreatment stage of the feedstock comprising lignocellulosic biomass makes it possible to improve the susceptibility of the cellulose to enzymatic hydrolysis.
• the pretreatment step according to step a) of the process according to the invention can be carried out according to all types of pretreatment of lignocellulosic biomass known to those skilled in the art.
• a prior conditioning step including for example grinding or stone removal can also be performed.
• the pretreatment step can be a thermal, chemical, mechanical and / or enzymatic treatment or a combination of these treatments.
• the pretreatment stage is chosen from a pretreatment under acidic conditions such as acid cooking or steam explosion under acidic conditions, a pretreatment in alkaline media such as sodium sulphide pretreatment ( Kraft process), an ARP process (Ammonia Recycle Percolation) or an AFEX process (Ammonia Fiber Explosion), an oxidizing pretreatment such as pretreatment using ozone, hydrogen peroxide, oxygen or peracetic acid, pretreatment without addition of chemical reagents such as steam explosion without addition of acid or pretreatment by washing with very hot water, or an organosolv process.
• a pretreatment under acidic conditions such as acid cooking or steam explosion under acidic conditions
• a pretreatment in alkaline media such as sodium sulphide pretreatment ( Kraft process), an ARP process (Ammonia Recycle Percolation) or an AFEX process (Ammonia Fiber Explosion)
• an oxidizing pretreatment such as pretreatment using ozone, hydrogen peroxide, oxygen or peracetic acid
• pretreatment without addition of chemical reagents such as
• the pretreatment stage is carried out by steam explosion, with or without the addition of acid.
• the effectiveness of pretreatment is measured both by the material balance at the end of pretreatment (recovery rate of sugars in monomeric or soluble oligomeric or solid polymer form) and also by the susceptibility to hydrolysis of cellulosic and hemicellulose residues. .
• the pretreated solid consists mainly of cellulose and lignin, the majority of hemicelluloses having been hydrolysed under acidic conditions.
• the solid is mainly composed of cellulose and hemicelluloses.
• the pretreated solid has a composition very similar to the charge.
• the solid is hemicellulose-depleted in comparison to the native biomass, but still retains a significant proportion .
• Pretreatments in acidic conditions tend to form degradative products of pentose and hexose sugars, for example furfural, 5-HMF.
• the formation of these degradation products increases with the severity of the pretreatment (heat, retention time, acidity).
• the hemicellulose of the lignocellulosic substrate is very easily hydrolyzed under acidic conditions and at high temperature. Nevertheless, pretreatment that is not very severe may not act sufficiently on the substrate and therefore reduce its susceptibility to enzymatic hydrolysis.
• the pretreatment with the dilute acid is generally carried out in the presence of sulfuric acid or hydrochloric acid diluted in a proportion of 0.5 to 10% relative to the substrate solids.
• Two methods are used: a first at a temperature> 60 ° C, continuous, which is suitable for low dry matter loads (5 to 10%) and a second method, discontinuous, carried out at temperatures often ⁇ 150 ° C, usable for dry matter concentrations between 10 and 40%. The higher the temperature, the greater the loss of solids. The residence times are dependent on the temperature used.
• Pretreatment by steam explosion is also known as steam explosion, steam gunning, explosive detente, steam pretreatment.
• the plant is quickly heated to high temperature (150 ° -250 ° C) by injection of steam under pressure. Stopping treatment is usually done by sudden decompression, called detente or explosion, which destructures the lignocellulosic matrix. The residence times vary from 10 seconds to a few minutes, for pressures ranging from 10 to 50 bars. This technique has been implemented either discontinuously or continuously. Some technologies offer water injection to cool the environment before decompression.
• the steam explosion may be preceded by an acid impregnation to increase the hydrolysis of hemicelluloses during cooking.
• Pretreatments in alkaline media have the advantage of generating much less polysaccharide degradation products. They present a viable alternative to acidic pretreatments, although their cost, especially for products implemented, is higher today.
• the pretreatments in an alkaline medium are for example a pretreatment with a mixture of sodium sulphide and sodium hydroxide, also called Kraft process, conventionally used in the production processes of paper products, called Kraft or "sulphate pulp", with the result of which is obtained paper pulp, pretreatment by ammonia fiber explosion, also called AFEX pretreatment (Ammonia Fiber Explosion) or pretreatment by percolation using ammonia with recycle, also called ARP pretreatment (Ammonia Recycle percolation).
• AFEX pretreatment Ammonia Fiber Explosion
• ARP pretreatment Ammonia Recycle percolation
• Some physicochemical pretreatments do not use the addition of chemical reagents.
• certain ester functions present in the hemicelluloses will hydrolyze, slightly acidifying the medium, which catalyzes the partial hydrolysis of the sugars present in the hemicellulose.
• the absence of chemical reagents makes its pretreatments less expensive, however, the reactivity in enzymatic hydrolysis of the thus pretreated cellulose is decreased.
• the Organosolv process consists of solubilizing and extracting lignin and hemicelluloses in an organic solvent (usually methanol or ethanol).
• An acidic catalyst (HCl or H 2 SO 4 ) is often added when the temperature used is below 185 ° C.
• the organic solvent is then extracted by evaporation and recycled.
• the thus pretreated filler may be subjected to a solid / liquid separation step and then optionally washed, preferably with water, before the enzymatic hydrolysis step.
• Pretreatment in acidic conditions or without chemical reagents leads to partial or almost complete hydrolysis of hemicelluloses, mainly monomeric (pentose and hexose) and soluble oligomeric sugars, depending on the type of biomass.
• the feedstock thus pretreated can be subjected before the enzymatic hydrolysis step b) to a separation step so as to recover a solid fraction and a liquid fraction. At least a part of the solid fraction is then sent to the enzymatic hydrolysis step b) and at least a portion of the liquid fraction can be recycled to the enzymatic hydrolysis step j). Indeed, the recycling of at least a portion of the liquid fraction containing the sugars from hemicellulose makes it possible to obtain a more concentrated solution of sugars at the end of the process.
• the conversion of the cellulose to alcohol comprises at least one step of enzymatic hydrolysis of the cellulose to glucose and a step of fermentation of the glucose into alcohol, these two steps can be carried out separately or simultaneously.
• the process is called the "SSF” method (according to the Anglo-Saxon term for Simultaneous Saccharification and Fermentation).
• the hydrolysis and fermentation steps can also be carried out according to other arrangements known to those skilled in the art, such as the "PSSF” (Presacchararification followed by Simultaneous Saccharification and Fermentation) or the "HHF” method. (Hybrid Hydrolysis and Fermentation).
• Step b) of enzymatic hydrolysis and step c) of alcoholic fermentation of the process according to the invention are carried out separately or simultaneously.
• steps b) and c) are carried out in two separate reactors.
• steps b) and c) are carried out in the same reactor.
• step b) of the process according to the invention the pretreated and optionally washed feedstock from step a) is sent to an enzymatic hydrolysis step to convert the pretreated feed into monomeric sugars.
• the enzymatic hydrolysis step utilizes cellulolytic and / or hemicellulolytic enzymes and produces an effluent comprising a hydrolyzate containing sugars and a solid and water insoluble residue.
• the enzymatic hydrolysis takes place at a pH of between 4.5 and 5.5 and preferably between 4.8 and 5.2. It usually takes place at a temperature between 40 and 60 ° C. Enzymatic hydrolysis is remeasured by means of enzymes produced by a microorganism. The enzymatic solution added to the pretreated substrate contains enzymes that break down cellulose into sugars.
• Microorganisms such as fungi belonging to the genera Trichoderma, Aspergillus, Penicillium or Schizophyllum, or anaerobic bacteria belonging for example to the genus Clostridium, produce these enzymes, notably containing cellulases and hemicellulases, suitable for the extensive hydrolysis of the cellulose and hemicelluloses.
• the cellulolytic and / or hemicellulolytic enzymes of step b) are produced by the microorganism Trichoderma reesei.
• the enzymatic hydrolysis is carried out with an enzymatic solution, often produced from the filamentous fungus such as for example Trichoderma reesei, or sometimes Aspergillus niger.
• filamentous fungus such as for example Trichoderma reesei, or sometimes Aspergillus niger.
• These fungi secrete an "enzymatic cocktail" composed of several different enzymes, up to 50, such as CBHI, CBHII involved in the hydrolysis of cellulose, and xylanases involved in the hydrolysis of hemicelluloses.
• the exact composition of the cocktail depends on the strain of fungus used and the conditions of culture.
• the sugars obtained by enzymatic hydrolysis are then fermented into alcohols such as ethanol, 1,3-propanediol, isopropanol, 1-butanol, isobutanol or 1,4-butanediol, alone or as a mixture.
• alcohols such as ethanol, 1,3-propanediol, isopropanol, 1-butanol, isobutanol or 1,4-butanediol, alone or as a mixture.
• the alcoholic fermentation carried out in step c) produces ethanol.
• the alcoholic fermentation carried out in step c) is provided by yeasts or other alcoholic microorganisms.
• the term "alcoholic fermentation” denotes a process for fermenting sugars into alcohol (s) solely by means of microorganisms.
• the alcoholic microorganisms used during the alcoholic fermentation step hexoses are preferably selected from yeasts and bacteria, possibly genetically modified.
• Saccharomyces cerevisiae When the alcoholic microorganism is a yeast, Saccharomyces cerevisiae is the one that is the most efficient. It is also possible to choose yeasts such as Schizosaccharomyces pombe or Saccharomyces uvarum or diastaticus. More thermophilic yeasts, such as Kluyveromyces fragilis (now often referred to as K. marxianus) are also of interest, especially when enzymatic hydrolysis and alcoholic fermentation are carried out simultaneously (SSF method).
• yeasts such as Schizosaccharomyces pombe or Saccharomyces uvarum or diastaticus. More thermophilic yeasts, such as Kluyveromyces fragilis (now often referred to as K. marxianus) are also of interest, especially when enzymatic hydrolysis and alcoholic fermentation are carried out simultaneously (SSF method).
• a genetically modified organism such as, for example, a yeast of the Saccharomyces cerevisiae type such as TMB 3400 (Ohgren et al., J. of Biotech 126, 488-498, 2006) may also be used.
• This yeast makes it possible to ferment in ethanol part of the pentoses during the ethylic fermentation step of the hexoses, when the glucose is in limiting concentration.
• Zymomonas mobilis When the alcoholic microorganism is a bacterium, Zymomonas mobilis is preferred which has an efficient assimilation route for the production of ethanol, or anaerobic bacteria of the Clostridium genus, for example, Clostridium acetobutylicum for the production of mixtures of alcohols and solvents such as acetone-butanol-ethanol (ABE) or isopropanol-butanol-ethanol (IBE), or Escherichia coli for the production of isobutanol for example.
• ABE acetone-butanol-ethanol
• IBE isopropanol-butanol-ethanol
• Escherichia coli Escherichia coli
• the alcoholic fermentation is preferably carried out at a temperature between 30 ° C and 40 ° C, and a pH between 3 and 65.
• Yeasts and preferably Saccharomyces cerevisiae are the microorganisms used very preferably. They have a better robustness, safety, and do not require sterility for the conduct of the process and installations. Yeasts of the genus Saccharomyces are able to ferment the only and unique hexoses (mainly glucose and mannose). These yeasts optimize ethanol hexoses and achieve conversion efficiencies in the range of 0.46 (w / w) to 0.48 (w / w), which is close to the maximum theoretical yield. which is 0.51 (w / w). Only pentoses and some marginal carbon sources are not used by these yeasts.
• the temperature is between 30 and 45 ° C.
• the pH is between 4 and 6.
• step d) of the process of the invention a step is performed to extract the alcohol from the fermented effluent from step c).
• This extraction step generally comprises at least one distillation step.
• a separation step is carried out for the effluent obtained either at the end of the fermentation step c) or at the end of the extraction step alcohol d) so as to produce a solid residue and a liquid fraction.
• This separation step can be carried out by the usual solid-liquid separation techniques, for example by decantation, by filtration or by centrifugation.
• This separation makes it possible to obtain a solid residue containing valuable sugar polymers and a liquid fraction (also called vinasses) containing unfermented sugars.
• step e) is recycled to the enzymatic hydrolysis step j).
• the liquid fraction resulting from step e) contains one or more alcohol (s).
• the recycling of at least a portion of this liquid fraction to step j) makes it possible to increase the final alcohol content (s) when performing in step j) enzymatic hydrolysis and fermentation.
• the proportion of each component in the extracted solid residue is a function of the initial substrate, the type of pretreatment performed and the conditions for carrying out the enzymatic hydrolysis and the fermentation.
• the amount of lignin is between 20 and 90% by weight, and more preferably between 30 and 85% by weight, the amount of cellulose between 10 and 70% by weight preferably between 20% and 60% by weight and the amount of hemicelluloses between 0 and 30% by weight, and preferably between 1 and 10% by weight.
• the solid residue composition will for example be:
• the amount of lignin is between 2 and 60% by weight, and more preferably between 3 and 50% by weight, the amount of cellulose between 10 and 70% by weight, preferably between 20 and 70% by weight. % and 60% by weight and the amount of hemicelluloses between 1 and 50% by weight, and preferably between 2 and 40% by weight.
• the amount of lignin is between 5 and 75% by weight, and more preferably between 5% and 60% by weight, the amount of cellulose between 10 and 75% by weight, preferably between 20% and 65% by weight and the amount of hemicelluloses between 1 and 60% by weight, and preferably between 2% and 45% by weight.
• the amount of lignin is between 10 and 80%, and more preferably between 10% and 65%, the amount of cellulose between 4 and 65% preferably between 10 and 60% and the amount of hemicelluloses between 1 and 60%, and preferably between 2 and 50%.
• the amount of lignin is between 20 and 90% by weight, and more preferably between 25% and 85% by weight.
• amount of cellulose between 10 and 70% by weight, preferably between 20% and 60% by weight and the amount of hemicelluloses between 1 and 50% by weight, and preferably between 2 and 40% by weight.
• the pretreatments and conditions for carrying out the enzymatic hydrolysis will be chosen so as to obtain a solid residue in step e) containing less than 30% by weight of the hemicelluloses contained in the biomass introduced in step a), preferably less than 20% by weight, and particularly preferably less than 10% by weight.
• step f) of the process according to the invention a washing and optionally drying of the solid residue obtained in step e) is optionally carried out.
• the washing is carried out in co-current or counter-current, possibly in several stages.
• the washing is carried out with water or a stream containing mainly water. Preferably, it is carried out with water.
• the washing solution obtained in the step of washing the solid residue f) is at least partly recycled in the enzymatic hydrolysis step j).
• the washing solution contains one or alcohol (s).
• the recycling of at least a portion of this washing solution in step j) makes it possible to increase the final alcohol content (s) when, in step j), enzymatic hydrolysis and fermentation are carried out.
• the washed solid residue can optionally be pressed to increase the percentage of dry matter contained in the solid.
• the optionally washed solid residue is then dried.
• the drying step can be carried out by any method known to those skilled in the art, for example by evaporation.
• Known technologies for evaporative drying are, for example, the rotary furnace, the moving bed, the fluidized bed, the heated worm, the contact with metal balls supplying heat. These technologies may optionally use a gas flowing at co or countercurrent such as nitrogen or any other gas inert under the conditions of the reaction.
• the drying step is carried out at a temperature greater than or equal to 20 ° C.
• the residual water content is less than 30% by weight, preferably less than 20% by weight and more preferably less than 10% by weight.
• the step of firing with hydrated inorganic salts makes it possible to obtain a solid fraction which contains most of the cellulose present in the solid residue resulting from stage f).
• This cellulose has the property of being particularly reactive in enzymatic hydrolysis.
• a liquid fraction containing the hydrated inorganic salt (s) is also obtained.
• step e) and / or f) is cooked in the presence of a hydrated inorganic salt of formula (I): MX n .n'H 2 O
• M is a metal selected from Groups 1 to 13 of the Periodic Table, X is an anion and
• n is an integer between 1 and 6 and
• n between 0.5 and 12.
• a mixture of hydrated inorganic salts may be used for cooking the solid residue from step e) and / or f).
• Anion X can be a monovalent, divalent or trivalent anion.
• the anion X is a halide anion selected from Cl “ , F “ , Br “ and, a perchlorate anion (CIO 4 " ), a thiocyanate anion (SCN “ ), a nitrate anion (NO 3 " ), a para-methylbenzene sulphonate anion (CH 3 -C 6 H 4 -SO 3 " ), an acetate anion (CH 3 COO " ), a sulfate anion (SO 4 2 " ), an oxalate anion (C 2 O 4 2”); ) or a phosphate anion (PO 4 3 " ) Even more preferably, the anion X is a chloride.
• the metal M in the formula (I) is chosen from lithium, iron, zinc or aluminum.
• the hydrated inorganic salt is selected from: LiCI.H 2 0, 2 0 LiCI.2H, ZnCl 2 .1, 5H 2 0, ZnCl 2 .2,5H 2 0, ZnCl 2 .4H 2 0 and FeCl 3 .6H 2 0.
• the salt is selected from ZnCl 2 .1, 5H 2 0, the ZnCl 2 .2,5H 0 2 and ZnCl 2 .4H 2 0.
• the firing temperature is between -20 ° C and 250 ° C, preferably between 20 and 160 ° C.
• the firing temperature is preferably between 100 ° C. and 160 ° C.
• the firing temperature is preferably between 20 ° C and 120 ° C.
• the duration of the cooking is between 0.5 minutes and 168 hours, preferably between 5 minutes and 24 hours, and even more preferably between 20 minutes and 12 hours.
• the firing step can be carried out in the presence of one or more organic solvents, chosen from alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol or tert-butanol, diols and polyols such as ethanediol, propanediol or glycerol, amino alcohols such as ethanolamine, diethanolamine or triethanolamine, ketones such as acetone or methyl ethyl ketone, carboxylic acids such as formic acid or acetic acid, dimethylformamide, dimethylacetamide, dimethylsulfoxide, acetonitrile, aromatic solvents such as benzene, toluene, xylenes, alkanes.
• organic solvents chosen from alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol or
• the firing step can be carried out in the absence of an organic solvent.
• the cooking medium of step e) consists of one or more hydrated inorganic salts.
• the dried solid fraction is present in an amount of between 4% and 40% by weight, based on the dry weight of the total mass of the solid fraction / hydrated inorganic salt mixture, preferably in a quantity of between 5% and 30% by weight. % weight
• a mixture of a solid fraction containing the pretreated cellulosic substrate and a liquid fraction containing the hydrated inorganic salt or salts and optionally an organic solvent are obtained. This mixture is sent in a solid / liquid separation step h).
• the separation step h) of the solid fraction is preferably carried out by precipitation by addition of at least one anti-solvent.
• the addition of the anti-solvent promotes the precipitation of the solid fraction.
• the separation step h) can be carried out by the usual solid-liquid separation techniques, for example by decantation, by filtration or by centrifugation.
• the anti-solvent used is a solvent or a mixture of solvents chosen from water, alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol or tert-butanol, diols and polyols such as ethanediol, propanediol or glycerol, amino alcohols such as ethanolamine, diethanolamine or triethanolamine, ketones such as acetone or methyl ethyl ketone, carboxylic acids such as formic acid or acetic acid, esters such as ethyl acetate or isopropyl acetate dimethylformamide, dimethylacetamide, dimethylsulfoxide, acetonitrile.
• alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol or tert-butanol
• the anti-solvent is selected from water, methanol or ethanol.
• the anti-solvent is water alone or as a mixture, and preferably alone.
• a so-called solid fraction and a liquid fraction are obtained.
• the solid fraction is composed of solid matter, between 5% and 60%, and preferably between 15% and 45%, and a liquid phase.
• the presence of liquid in this fraction is related to the limitations of liquid / solid separation devices.
• the solid material contains most of the cellulose of the solid residue from step e), between 60% and 100%, and preferably between 75% and 99% of the cellulose introduced into the firing step g).
• the liquid fraction contains the hydrated inorganic salt or salts used during the baking step, and optionally the antisolvent. Due to the elimination of hemicellulose by steps a) pretreatment and b) enzymatic hydrolysis, this fraction contains very little hemicellulose (or products derived from hemicellulose). It may contain lignin.
• the solid fraction obtained at the end of the separation step h) may optionally be subjected to additional treatments (step i). These additional treatments may in particular be intended to eliminate the traces of hydrated inorganic salts in this solid fraction.
• Step i) of treatment of the solid fraction obtained in step h) can be carried out by one or more washes, neutralization, pressing, and / or drying.
• the washes can be carried out with antisolvent or with water.
• the washes may also be made with a stream from a processing unit of products from the pretreatment process of the present invention.
• the washes can be made with a stream from this cellulosic ethanol production unit.
• the neutralization can be carried out by suspending the solid fraction obtained in step h) in water and adding a base.
• base we refer to any chemical species which, when added to water, gives an aqueous solution of pH greater than 7.
• the neutralization can be carried out by an organic or inorganic base.
• bases that can be used for the neutralization include sodium hydroxide, potassium hydroxide, sodium carbonate and potassium, sodium bicarbonate and potassium and ammonia.
• the solid fraction obtained at the end of the separation step h) may optionally be dried or pressed to increase the percentage of dry matter contained in the solid.
• step j) of the process according to the invention a step of enzymatic hydrolysis of the solid fraction obtained in step h) and / or i) is carried out to convert the cellulose contained in the solid fraction. in solution of sugars containing in particular monosaccharides such as glucose.
• step j) of the process according to the invention enzymatic hydrolysis and alcoholic fermentation steps of the solid fraction obtained in step h) and / or i) are carried out to convert the cellulose contained in in the solid fraction in solution of sugars and transform the solution of sugars into alcohols.
• the enzymatic hydrolysis in this step is carried out in the same manner and in the same ranges as those described for step b).
• the operating conditions of the enzymatic hydrolysis may be identical to or different from those of step b).
• the enzymatic cocktail introduced in this second enzymatic hydrolysis has a composition that is identical or different from the enzymatic cocktail introduced into the enzymatic hydrolysis of step b).
• the alcoholic fermentation in this step is carried out in the same manner and in the same ranges as those described for step c).
• the operating conditions of the fermentation may be identical to or different from those of step c).
• the alcoholic microorganism introduced into this second alcoholic fermentation may be identical or different from the alcoholic microorganism introduced into the alcoholic fermentation of step c).
• the fermentation must obtained is then distilled to separate the vinasses and the alcohol produced.
• the alcoholic fermentation of step j) produces ethanol.
• Step j) of enzymatic hydrolysis and alcoholic fermentation of the process according to the invention are carried out separately or simultaneously (SSF method).
• the lignocellulosic biomass is introduced via the pipe (2) into the reactor (4) in which the pretreatment step a) takes place.
• the pretreatment step a) can be carried out according to all the techniques known to those skilled in the art, preferably the pretreatment by steam explosion with or without the addition of acid.
• the reagent or reagents that may be necessary are introduced via line (6).
• the necessary water and / or steam are optionally introduced into the pipe (8).
• a pre-treated charge is withdrawn via line (10).
• a solid / liquid separation is advantageously carried out following the pretreatment to exit in the pipe (14) all or part of the liquid flow that contains solubilized hemicelluloses during pretreatment.
• the line (12) may be used to supply a washing liquid, most preferably water, to improve the recovery of sugars from hemicelluloses.
• the flow extracted by the pipe (14) is a sugar solution. This stream (14) can be recycled at less partially in the chamber (64) of the enzymatic hydrolysis step j) (not shown).
• the pretreated feedstock (10) is then sent to the reactor (16) in which the enzymatic hydrolysis step (b) (16a) and the alcoholic fermentation step (16b) take place.
• the reactor (16) in which the enzymatic hydrolysis step (b) (16a) and the alcoholic fermentation step (16b) take place.
• One or more reactors can be implemented, these reactors can be similar or of different geometry with similar or different agitation systems. This step can be performed in batch mode, semi-continuous or continuous mode, or in combination, depending on the reactors.
• the units of enzymatic hydrolysis and alcoholic fermentation are shown separately from one another, however it is possible to have a single reactor in which hydrolysis and fermentation are carried out simultaneously. (SSF process).
• water may be added via line (18) to adjust the percentage of dry matter used in this step.
• the enzyme cocktail in particular containing cellulases and / or hemicellulases, is introduced via line (20).
• the alcoholic microorganisms used for the alcoholic fermentation are introduced through line (21).
• the flow (22) leaving the reactor (16) is a mixture of alcohols, a liquid fraction containing unfermented sugars (called vinasses) and a solid and insoluble residue in water.
• the solid residue is partly composed of cellulose and hemicellulose that has not been hydrolysed and lignin.
• the solid fraction of the flow (22) contains less than 30% by weight, preferably less than 20% by weight. and very preferably less than 10% by weight of the hemicelluloses initially contained in the biomass introduced into the pipe (2).
• the flow (22) is sent into the alcohol extraction device (23) (step d).
• the extraction is preferably carried out by distillation and allows the alcohol to be recovered via the line (25).
• the remaining stream (27) containing the solid residue and the liquid fraction containing unfermented sugars is fed into the separation device (24).
• a liquid fraction containing unfermented sugars (26) and the solid residue (28) are obtained.
• the liquid fraction may be at least partly recycled in the device (64) of the enzymatic hydrolysis step j) (not shown).
• the solid residue (28) contains a solid phase, and a liquid phase whose composition is similar to the flux (26), due to the current limitations of solid / liquid separation equipment.
• the solid residue (28) can be fed to a washing step (32) (step f), wherein a washing liquid, preferably water, is introduced into the line (30).
• the washing solution is extracted via the pipe (36), it contains more than 70%, and preferably more than 85% and even more preferably more than 90% of the monomeric (soluble) sugars contained in the stream (28).
• This washing solution may be recycled at least partly in the chamber (64) of the enzymatic hydrolysis step j) (not shown).
• the washed solid residue (34) is sent to a drying device (38) (step f).
• the optionally washed and optionally dried solid residue is then introduced via the pipe (40) into the cooking reactor (42) in which the cooking step g) takes place.
• the cooking medium comprising one or more hydrated inorganic salts and optionally an organic solvent is introduced through the line (44).
• a mixture containing the treated solid residue, the hydrated inorganic salt or salts and optionally an organic solvent is withdrawn via line (46).
• This mixture is sent into the liquid / solid separation device (48) in which the separation step h) takes place.
• the optional anti-solvent is added via line (50).
• a solid fraction (52) and a liquid fraction (54) containing the hydrated inorganic salt (s) are obtained.
• the solid fraction (52) may optionally be subjected to additional treatments (step i) carried out in the device (56).
• the agents that may be necessary for the treatment (s) carried out in the enclosure (56) are introduced via the pipe (58). Any residues of this treatment (s) are withdrawn by the pipe (60).
• the treated solid fraction is withdrawn through line (62) and sent to the reactor (64) (step j) in which an enzymatic hydrolysis step (64a) is carried out.
• the enzymatic cocktail is introduced via line (66), this cocktail may be identical or different from the enzymatic cocktail (20) implemented in step b).
• water may be added via line (68) to adjust the percentage of dry matter used in this step.
• a sweet solution is removed by the line (70a).
• the treated solid fraction is withdrawn via line (62) and is sent to the reactor (64) (step j) in which an enzymatic hydrolysis step (64a) and an alcoholic fermentation step (64b) are performed.
• the enzymatic cocktail is introduced via line (66), this cocktail may be identical or different from the enzymatic cocktail 20 implemented in step b).
• water may be added via line (68) to adjust the percentage of dry matter used in this step.
• the alcoholic microorganisms used for the alcoholic fermentation are introduced via the pipe (69), these microorganisms have a composition identical to or different from the microorganisms 21. The fermentation must obtained is then distilled (not shown) to separate the vinasses and the product alcohol (70b).
• Alcohols and / or sugars are thus obtained by the process according to the invention by steps d) (stream (25)), e) (stream (26), j) (stream (70 a and b)) and optionally f) (stream 36)).
• steps d) (stream (25)), e) (stream (26), j) (stream (70 a and b)) and optionally f) (stream 36)).
• a solution of sugars resulting from the hemicellulose obtained after step a) (flux (14)) is obtained if an acid pretreatment or without the addition of chemical reagent is carried out, completed with a solid / liquid separation and optionally washing before step b).
• the separation step h) is carried out with the addition of an anti-solvent
• the additional treatment carried out in the enclosure (56) (step i)) consists of one or more washings carried out with the anti-solvent introduced via the pipe (58).
• the liquid (50) after washing contains mainly the solvent and hydrated inorganic salt.
• This liquid (50) is used as an anti-solvent in the separation step h).
• the anti-solvent is water.
• FIG. 3 relates to the recycling of the inorganic salt contained in different liquid fractions obtained during the process.
• At least a portion of the liquid fraction obtained in the separation step h) (54) is sent to a purification step (72), called step k), making it possible to concentrate the inorganic salt contained in the liquid fraction and obtaining a liquid fraction containing the concentrated inorganic salt (74) and another inorganic salt-depleted liquid fraction (76), said liquid fraction containing the concentrated inorganic salt (74) being then at least partially recycled in the cooking step g).
• the purification step k) may in particular be a step of separation of the inorganic salt hydrate and the anti-solvent.
• This separation can be carried out by any method known to those skilled in the art, such as, for example, evaporation, precipitation, extraction, passage over ion exchange resin, electrodialysis, chromatographic methods, solidification.
• hydrated inorganic salt by lowering the temperature or adding a third body, reverse osmosis.
• the additives that may be necessary for this step are introduced via the line (78) into the chamber (72).
• a liquid fraction is obtained containing the concentrated inorganic salt (74) which is advantageously recycled at least in part to the cooking reactor (42) (step g).
• water may be added to the stream (74) through the line (80) to adjust the water stoichiometry to obtain a hydrated inorganic salt of a composition identical to that introduced by the line (44).
• the hydrated inorganic salt obtained has the same composition than that introduced by the pipe (44).
• the liquid fraction (74) may contain all or part of the organic solvent.
• the inorganic salt-depleted liquid fraction (76) may contain the anti-solvent, the organic solvent, residues of biomass-derived products and hydrated inorganic salt.
• the inorganic salt-depleted liquid fraction (76) contains less than 50% of the hydrated inorganic salt initially contained in the fraction (54). Even more preferably, the inorganic salt-depleted liquid fraction (76) contains less than 25% of the hydrated inorganic salt initially contained in the fraction (54).
• step h) When step h) is carried out with the addition of an antisolvent, the antisolvent is recovered mainly in the liquid fraction depleted in inorganic salt (76) and can be recycled (not shown) to step h) after any reprocessing, or to step i) in the case of the implementation of FIG.
• step i) of treatment of the solid fraction obtained in step h) is carried out by one or more washes to obtain a treated solid fraction (62) and a liquid fraction (60), said the liquid fraction being at least partly sent to a purification step (72), called step k), for concentrating the inorganic salt contained in the liquid fraction and obtaining a liquid fraction containing the concentrated inorganic salt (74) and another inorganic salt-depleted liquid fraction (76), said liquid fraction containing the concentrated inorganic salt (74) being then at least partially recycled to the firing step g).
• step i) is carried out with the addition of an antisolvent, any residues of this treatment (s) are withdrawn by the line (60), then either purged (84) or sent to the enclosure (72).
• the antisolvent (58) added in step i) is separated during the purification step (72) and recycled in step i).

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