WO2010069583A1

WO2010069583A1 - Process for the production of sugars from biomass

Info

Publication number: WO2010069583A1
Application number: PCT/EP2009/009109
Authority: WO
Inventors: Daniele Bianchi; Anna Maria Romano
Original assignee: Eni S.P.A.
Priority date: 2008-12-18
Filing date: 2009-12-16
Publication date: 2010-06-24
Also published as: AR074794A1; ITMI20082251A1; IT1394398B1

Abstract

Process for the production of sugars from biomass including at least one polysaccharide which comprises putting said biomass in contact with an aqueous solution of at least one organic acid, at a temperature higher than or equal to 160°C, preferably from 160 °C to 230 °C. The sugars thus obtained can be advantageously used as carbon sources in fermentation processes for the production of alcohols (e.g. ethanol, butanol). Said alcohols can be advantageously used as biofuels for motor vehicles, or as components which can be added to fuels for motor vehicles.

Description

PROCESS FOR THE PRODUCTION OF SUGARS FROM BIOMASS

The present invention relates to a process for the production of sugars from biomass including at least one polysaccharide . More specifically, the present invention relates to a process for the production of one or more sugars from biomass including at least one polysaccharide which comprises the treatment of said biomass with an aqueous solution of at least one organic acid, at a temperature higher than or equal to 160⁰C.

The sugars thus obtained can be advantageously used as carbon sources in fermentation processes for the production of alcohols (e.g. ethanol, butanol) . Said alcohols can be advantageously used as biofuels for motor vehicles, or as components which can be added to fuels for motor vehicles.

Generally speaking, biomass is any substance with an organic, vegetable or animal matrix, which can be used for energy purposes, for example as raw material for the production of biofuels or components which can be added to fuels. Biomass can therefore form a renewable energy source as an alternative to traditional raw materials of a fossil origin, normally used in the production of fuels. For this purpose, lignocellulosic biomass is particularly useful.

The production of sugars from biomass, in particular lignocellulosic biomass, is known in the art.

Lignocellulosic biomass is a complex structure comprising three main components: cellulose, hemicellulose and lignin. Their relative quantities vary according to the type of lignocellulosic biomass used. For example, in the case of plants, said quantities vary according to the species and age of the plant.

Cellulose is the greatest constituent of lignocellulosic biomass and is generally present in quantities ranging from 30% by weight to 60% by weight with respect to the total weight of the lignocellulosic biomass. Cellulose consists of glucose molecules (from about 500 to 10,000 units) bound to each other through a β-1,4 glucoside bond. The establishment of hydrogen bonds between the chains causes the formation of crystalline domains which give resistance and elasticity to vegetable fibres. In nature, it can only be found in its pure state in annual plants such as cotton and flax, whereas in ligneous plants it is always accompanied by hemicellulose and lignin.

Hemicellulose, which is generally present in a quantity ranging from 10% by weight to 40% by weight with respect to the total weight of the lignocellulosic biomass appears as a mixed polymer, relatively short

(from 10 to 200 molecules) and branched, made up of both sugars with six carbon atoms (glucose, mannose, galactose) and also sugars with five carbon atoms

(xylose, arabinose) . Some important properties of vegetable fibres are due to the presence of hemicellulose, of which the main property is that of favouring the imbibition of said vegetable fibres, when water is present, causing swelling. Hemicellulose also has adhesive properties and therefore tends to harden or develop a horny consistency, with the consequence that said vegetable fibres become rigid and are imbibed more slowly.

Lignin is generally present in a quantity ranging from 10% by weight to 30% by weight with respect to the total weight of the lignocellulosic biomass. Its main function consists in binding and cementing the various vegetable fibres with each other giving the plant compactness and resistance and also provides protection against insects, pathogen agents, lesions and ultraviolet light. It is mainly used as fuel but is also currently widely used in industry as a disperser, hardener, emulsifying agent, for plastic laminates, cartons and rubber products. It can also be chemically treated to produce aromatic compounds, of the vanillin, syringaldehyde , p-hydroxybenzaldehyde type, which can be used in pharmaceutical chemistry, or in the cosmetic and food industry.

In order to optimize the transformation of lignocellulosic biomass into products for energy use, subjecting said biomass to a preliminary treatment is known, in order to separate the lignin and hydrolyze the cellulose and hemicellulose to simple sugars such as, for example, glucose and xylose, which can then be subjected to fermentation processes to produce alcohols.

The process normally used for the above purpose is acid hydrolysis, which can be carried out in the presence of strong mineral acids, generally H₂SO₄, HCl or HNO₃, diluted or concentrated. This process however has various drawbacks mainly due to the fact that in order to hydrolyze both of the polysaccharide components of the biomass, i.e. cellulose and hemicellulose, drastic conditions are required due to the high stability of the cellulose. The severity of the treatment, in particular the high temperatures normally used, leads to the formation of by-products deriving from the dehydration of the sugars and partial depolymerization of the lignin. These by-products, in particular furfural, hydroxymethylfurfural and phenolic compounds, act as growth inhibitors of the microorganisms normally used in the subsequent fermentation processes of the sugars to alcohols, causing a significant decrease in the efficiency and productivity of said processes.

If, on the contrary, the acid hydrolysis is carried out at low temperatures, for example lower than 140⁰C, a limited destructuring of the lignocellulosic biomass can be obtained, said destructuring being necessary for freeing the cellulose fibres from the lignin lattice which is covering them to allow them to be advantageously used in the subsequent hydrolysis steps, for example enzymatic. It is in fact difficult for the enzymes normally used (for example, cellulase) in the enzymatic hydrolysis to reach the cellulose fibres covered by lignin. The known processes also have another drawback: when inorganic acids (e.g. sulfuric acid) are used, for example, at the end of the acid hydrolysis, an aqueous phase is obtained including the sugars pentose and hexose deriving from the hydrolysis of cellulose and hemicellulose having an acid pH: said aqueous phase must therefore be subjected to neutralization by the addition, for example, of calcium oxide, calcium hydroxide, or barium hydroxide, with the consequent formation of salts (e.g. calcium sulfate, calcium sulfate dihydrate (gypsum) , barium sulfate) which precipitate and must therefore be separated from said phase before the same is subjected to the fermentation processes mentioned above. It is consequently impossible to recover and re-use said inorganic acid. Furthermore, the salts produced must be subsequently disposed of by suitable treatment with a consequent increase in the production costs . Alternatively, methods are also described for the recovery and recycling of the mineral acid with the use of membranes or ion exchange resins . The recovery efficiency, however, is never quantitative and a part of the acid remains in the saccharine solution and in any case requires a neutralization step. Processes are also described, which comprise the separation of the sugars by precipitation with hydrosoluble organic solvents, for example aldehydes or ketones, and the recycling of the aqueous solution containing acid, after evaporation of the solvent. The saccharine precipitate is re-dissolved in water and, also in this case, requires a neutralization step to eliminate the residual acid.

American patent US 5,562,777 (Arkenol process) , for example, describes the hydrolysis of the cellulose and hemicellulose components of biomasses using H₂SO₄. At the end of the hydrolysis, the sugars are separated by means of chromatography and 95-99% of the acid is recovered and recycled. The residual acidity in the hydrolyzed solution is neutralized with calcium oxide. Under these conditions, there is coproduction of 40 g of CaSO₄ per kg of biomass treated.

US 6,090,595 (Iogen process) describes the hydrolysis of the cellulose and hemicellulose components of biomasses using H₂SO₄. The acidity of the solution of hydrolyzed products is neutralized with BaCO₃ with the coproduction of 600 g of BaSO₄ per kg of biomass treated.

US 6,022,419 describes the hydrolysis of the cellulose and hemicellulose components of biomasses using a mineral acid, for example H₂SO₄. The acidity of the solution of hydrolyzed products, if neutralized with calcium oxide, leads to the coproduction of 29 g of CaSO₄ per kg of biomass treated.

US 4,556,430 describes the hydrolysis of the cellulose and hemicellulose components of biomasses using H₂SO₄. The acidity of the solution of hydrolyzed products, if neutralized with calcium oxide, leads to the coproduction of 56 g of CaSO₄ per kg of biomass treated.

US 4,612,286 describes the hydrolysis of the cellulose and hemicellulose components of biomasses using H₂SO₄. The acidity of the solution of hydrolyzed products is neutralized with calcium oxide with an average coproduction of 162 g of CaSO₄ per kg of biomass treated. US 5,411,594 describes the hydrolysis of the cellulose and hemicellulose components of biomasses in a two-step process using H₂SO₄. The acidity of the solution of hydrolyzed products, if neutralized with calcium oxide, leads to the coproduction of 185 g of CaSO₄ per kg of biomass treated.

WO 02/02826 describes the hydrolysis of the cellulose and hemicellulose components of biomasses using H₂SO₄, in particular mixtures of H₂SO₄ (50%) and H₃PO₄ (20%) . The sugars produced are precipitated from the aqueous solution by the addition of methylethylketone and then re-dissolved in water. The acidity of the solution obtained is neutralized with calcium oxide leading to an average coproduction of 150 g of CaSO₄ per kg of biomass treated.

US 5,221,357, US 5,536,325, US 5,366,558 describe the hydrolysis of the cellulose and hemicellulose components of biomasses in a two-step process using HNO₃. The acidity of the solution of hydrolyzed products must be neutralized for use in fermentation.

US 6,423,145 describes the hydrolysis of the cellulose and hemicellulose components of biomasses using mineral acids such as H₂SO₄, HCl or HNO₃. The acidity of the solution of hydrolyzed products must be neutralized for use in fermentation.

US 5,879,463 describes the hydrolysis of the cellulose and hemicellulose components of biomasses using mineral acids (e.g. H₂SO₄) in a mixture with organic solvents (e.g. acetone, methanol, ethanol) and water. The acidity of the solution of hydrolyzed products must be neutralized for use in fermentation.

The Applicant has now found that the production of sugars from biomass, in particular from biomass including at least one polysaccharide, can be advantageously effected by means of a process which comprises the treatment of said biomass with an aqueous solution of at least one organic acid, at a temperature not higher than or equal to 16O⁰C.

Numerous advantages are obtained with this process. This process, for example, allows a high yield of sugars pentose and hexose, deriving from the acid hydrolysis of said biomass, to be obtained, which can be subsequently used as carbon source in fermentation processes for the production of alcohols (e.g. ethanol, butanol) . Said alcohols can be advantageously used as biofuels for motor vehicles, or as components which can be added to fuels for motor vehicles.

Furthermore, the use of these particular acids allows a reduction in the formation of by-products such as, for example, furfural, hydroxymethylfurfural, phenolic compounds which, as indicated above, act as growth inhibitors of the micro-organisms normally used in the subsequent fermentation process of the sugars.

Another important advantage lies in the fact that this process allows the organic acid to be recovered, which can therefore be recycled to the above process . This recovery also avoids neutralization and therefore the production of salts and their subsequent disposal.

An object of the present invention therefore relates to a process for the production of one or more sugars from biomass including at least one polysaccharide which comprises putting a biomass in contact with an aqueous solution of at least one organic acid, at a temperature higher than or equal to 160⁰C.

One or more sugars are preferably produced, having a number of carbon atoms varying from 5 to 6. Even more preferably, glucose is produced, possibly in a mixture with xylose. Mannose, galactose and/or arabinose can be additionally present.

At least one organic acid is preferably used, selected from: alkylsulfonic acids, arylsulfonic acids or halogenated carboxylic acids. In particular, the alkylsulfonic acids used in the present invention have the formula R-SO₃H wherein R is a linear, branched or cyclic alkyl, saturated or unsaturated, preferably containing from 4 to 16 carbon atoms, even more preferably from 8 to 12.

Alkylsulfonic acids which can be well used are, for example, octylsulfonic acid and dodecylsulfonic acid.

The arylsulfonic acids used in the present invention have the formula Ar(SO₃H)_n wherein n is selected from 1 and 2, and Ar is an aryl group, optionally alkyl-substituted, preferably containing from 6 to 12 carbon atoms, even more preferably selected from 7 to 10. Arylsulfonic acids which can be well used are, for example, para-toluenesulfonic acid, 1 -naphthalene - sulfonic acid, 2-naphthalenesulfonic acid, 2,5- naphthalenedisulfonic acid and 1,5- naphthalenedisulfonic acid.

The halogenated carboxylic acids used in the present invention have the formula R_x-COOH, wherein R_x is a linear, branched or cyclic alkyl group, containing at least one halogen substituent. R_x preferably contains from 1 to 10 carbon atoms, even more preferably from 1 to 8. The halogen is preferably selected fluorine and chlorine. Halogenated carboxylic acids which can be well used are, for example, trifluoroacetic acid, dichloroacetic acid, trichloroacetic acid and perfluorooctanoic acid.

A particularly preferred aspect of the present invention is to use para-toluenesulfonic acid, 2- naphthalenesulfonic acid, 1, 5-naphthalene-disulfonic acid, or mixtures thereof.

It is preferable to operate at a temperature which varies from 160 to 23O⁰C, even more preferably from 180 to 210⁰C. For the purposes of the present invention and following claims, the definitions of the numerical ranges always comprise the extremes unless otherwise specified.

According to a preferred embodiment of the present invention, said polysaccharide can be selected from cellulose, hemicellulose, or mixtures thereof.

Cellulose, or mixtures of hemicellulose and cellulose, are particularly preferred.

According to a further preferred embodiment of the present invention, said biomass is a lignocellulosic biomass . As already mentioned, lignocellulosic biomass comprises three components: hemicellulose, cellulose and lignin.

Said lignocellulosic biomass is preferably selected from:

- products of crops expressly cultivated for energy use (for example, miscanthus, foxtail millet and common cane), including waste products, residues and scraps of said crops or their processing;

- products of agricultural cultivations, forestation and silviculture, comprising wood, plants, residues and waste products of agricultural processing, forestation and silviculture;

- waste of agro-food products destined for human nutrition or zootechnics,-

- residues, not treated chemically, of the paper industry;

- waste products coming from the differentiated collection of solid urban waste (e.g. urban waste of a vegetable origin, paper) .

According to preferred embodiment of the present invention, said biomass can be subjected to a preliminary milling process before being put in contact with said aqueous solution of at least one organic acid. Said biomass is preferably milled until particles having a diameter ranging from 0.1 mm to 10 mm, more preferably ranging from 0.5 mm to 4 mm, are obtained. Particles having a diameter of less than 1 mm are particularly preferred.

According to a preferred embodiment of the present invention, said biomass is present in the reaction mixture in a quantity ranging from 5% by weight to 40% by weight, preferably from 10% by weight to 20% by weight, with respect to the total weight of the reaction mixture.

For the purposes of the present invention and following claims, the term "reaction mixture" refers to the mixture comprising the biomass and aqueous solution of at least one organic acid, said reaction mixture being obtained by putting said biomass in contact with said aqueous solution.

According to a preferred embodiment of the present invention, said at least one organic acid is soluble in water and can be extracted with an organic solvent insoluble in water.

For the purposes of the present invention and following claims, the term "organic acid soluble in water" refers to an organic acid which has a solubility in distilled water at 25°C, of at least 0.5 g/100 ml of distilled water, preferably at least 2 g/100 ml of distilled water. For the purposes of the present invention and following claims, the term "organic acid which can be extracted with an organic solvent insoluble in water" refers to an organic acid which can be extracted with an organic solvent insoluble in water with a yield of at least 80%, preferably at least 90%, said yield being calculated with respect to the total quantity of organic acid present in the aqueous solution.

For the purposes of the present invention and following claims, the term "organic solvent insoluble in water" refers to an organic solvent which has a solubility in distilled water, at 25°C, lower than 4% by volume, preferably lower than 2% by volume.

According to a preferred embodiment of the present invention, said at least one organic acid is present in the aqueous solution at a concentration of 0.1% by weight to 5% by weight, preferably from 0.5% by weight to 2% by weight, with respect to the total weight of the aqueous solution. Said organic acid acts as catalyst for the acid hydrolysis of said biomass . In particular, when the starting biomass is a lignocellulosic biomass, said organic acid specifically acts as catalyst for the acid hydrolysis of the cellulose and hemicellulose . According to a preferred embodiment of the present invention, said biomass is put in contact with said aqueous solution for a time ranging from 1 to 8 hours, preferably from 2 to 5 hours.

Said biomass is put in contact with said aqueous solution in reactors known in the art, such as, for example, autoclaves, or extruders. According to a preferred embodiment of the present invention, said process also comprises obtaining a first solid phase and a first aqueous phase.

According to a further preferred embodiment of the present invention, said first solid phase comprises lignin.

According to a preferred embodiment of the present invention, said first aqueous phase comprises one or more sugars containing from 5 to 6 carbon atoms and said at least one organic acid. Said at least one organic acid is the organic acid which is put in contact with the biomass.

Said first aqueous phase preferably contains glucose, possibly in a mixture with xylose. Said xylose derives from the acid hydrolysis of hemicellulose, said glucose derives from the acid hydrolysis of cellulose. Mannose, galactose and/or arabinose can be additionally present .

Said phases can be separated by means of techniques known in the art such as, for example, filtration, centrifugation. Said phases are preferably separated by filtration.

According to a preferred embodiment of the present invention, said first aqueous phase is subjected to extraction with an organic solvent insoluble in water. Said organic solvent insoluble in water is preferably selected from: halogenated hydrocarbons such as methylene chloride, monochlorobenzene, dichlorobenzene or mixtures thereof; aromatic hydrocarbons such as toluene, xylene, or mixtures thereof; C4-C6 aliphatic alcohols, such as n-butanol, n-pentanol, and mixture of thereof . Toluene and mixtures of aromatic hydrocarbons and C4-C6 aliphatic alcohols, such as toluene and n- butanol, are particularly preferred.

Said organic solvent insoluble in water is subsequently evaporated, obtaining a second solid phase comprising said at least one organic acid (i.e. the organic acid which is put in contact with the biomass) and a second aqueous phase comprising one or more sugars containing from 5 to 6 carbon atoms . Said second aqueous phase preferably contains glucose, possibly mixed with xylose. Mannose, galactose and/or arabinose can be additionally present.

As specified above, the process, object of the present invention, therefore allows the organic acid to be recovered, which is put in contact with the biomass with a high yield, i.e. with a yield of at least 80%, preferably at least 90%, said yield being calculated with respect to the total quantity of organic acid which is put in contact with the biomass. Said organic acid can therefore be subsequently re-used according to the process, object of the present invention.

According to a preferred embodiment of the present invention, said process also comprises re-using said organic acid.

Said second aqueous phase comprising at least one sugar containing from 5 to 6 carbon atoms, can be directly used in fermentation processes for the production of alcohols (e.g. ethanol, butanol) . Said alcohols can be advantageously used as biofuels for motor vehicles, or as components which can be added to fuels for motor vehicles.

A summarizing scheme of the process, object of the invention is provided in figure 1. The process, object of the present invention therefore allows one or more sugars containing from 5 to 6 carbon atoms to be obtained, in particular preferably glucose deriving from the hydrolysis of cellulose, and possibly xylose deriving from the acid hydrolysis of hemicellulose, with a high yield. More in particular, said process allows a yield of glucose higher than or equal to 70%, to be obtained, said yield being calculated with respect to the total quantity of glucose present in the starting biomass, and a yield of xylose higher than or equal to 80%, said yield being calculated with respect to the total quantity of xylose present in the starting biomass . The process, object of the present invention, also allows high yields of lignin to be obtained.

The quantity of sugars contained in the starting biomass as also the quantity of sugars obtained after acid hydrolysis, can be determined by means of techniques known in the art such as, for example High

Performance Liquid Chromatography (HPLC) .

Said second aqueous phase comprising glucose, can be directly used as raw material in fermentation processes for the production of alcohols (e.g. ethanol, butanol) , as described for example in US 5562777 and in US 2008/0044877. Said alcohols can be advantageously used as biofuels for motor vehicles, or as components which can be added to fuels for motor vehicles. The solid phase containing lignin can be upgraded as fuel, for example as fuel for producing the energy necessary for sustaining the treatment processes of the biomass .

Some illustrative and non- limiting examples are provided for a better understanding of the present invention and for its embodiment. EXAMPLE 1

10 g of milled coniferous wood flour (particle diameter < 0.2 mm) are added to a solution of 1 g of 2- naphthalenesulfonic acid in 100 ml of water. The mixture was kept under stirring in an autoclave, at

200⁰C for 4 hours. After cooling, the solid phase is separated by filtration and dried obtaining 2.5 g of lignin with a purity >95%, corresponding to a yield to lignin >95%

(the lignin content of the starting biomass is equal to 25% by weight) .

The aqueous solution is extracted with 300 ml of a mixture of toluene/n-butanol 3:1 by volume. The organic phase is then separated and the solvent is evaporated at reduced pressure, obtaining 0.97 g of solid residue consisting of 2-naphthalenesulfonic acid (recovery yield = 97%) . After extraction, the aqueous phase has a pH equal to 6 and contains a glucose with a concentration equal to 4.2%, corresponding to a hydrolysis yield of 77% (calculated with respect to the cellulose component of the starting biomass, which is equal to 50% by weight) . EXAMPLE 2

200⁰C for 4 hours.

After cooling the solid phase is separated by filtration and dried obtaining 2.5 g of lignin with a purity >95%, corresponding to a yield to lignin >95%.

The aqueous solution is extracted with 300 ml of toluene at 100⁰C. The organic phase is then separated and the solvent is evaporated at reduced pressure, obtaining 0.99 g of solid residue consisting of 2- naphthalenesulfonic acid (recovery yield = 99%) . After extraction, the aqueous phase has a pH equal to 6 and contains a glucose with a concentration equal to 4.2%, corresponding to a hydrolysis yield of 77% (calculated with respect to the cellulose component of the starting biomass, which is equal to 50% by weight) . EXAMPLE 3 10 g of milled coniferous wood flour (particle diameter < 0.2 mm) are added to a solution of 1 g of 2- naphthalenesulfonic acid in 100 ml of water. The mixture was kept under stirring in an autoclave, at 200⁰C for 4 hours. After cooling the solid phase is separated by filtration and dried obtaining 2.5 g of lignin with a purity >95%, corresponding to a yield to lignin >95%.

The aqueous solution is extracted with 300 ml of xylene at 100⁰C. The organic phase is then separated and the solvent is evaporated at reduced pressure, obtaining 0.90 g of solid residue consisting of 2- naphthalenesulfonic acid (recovery yield = 90%) . After extraction, the aqueous phase has a pH equal to 6 and contains a glucose with a concentration equal to 4.2%, corresponding to a hydrolysis yield of 77% (calculated with respect to the cellulose component of the starting biomass, which is equal to 50% by weight) .

Claims

1) Process for the production of one or more sugars from biomass including at least one polysaccharide which comprises putting said biomass in contact with an aqueous solution of at least one organic acid at a temperature greater than or equal to 160 ⁰C.

2) Process according to claim 1 wherein said organic acid is chosen from among alkylsulfonic acids, arylsulfonic acids and halogenated carboxylic acids. 3) Process according to claim 2 wherein the alkylsulfonic acids have the R-SO₃H formula where R is a saturated or unsaturated, linear, branched or cyclic alkyl .

4) Process according to claim 3 wherein R contains from 4 to 16 carbon atoms.

5) Process according to claim 2 wherein the arylsulfonic acids have the Ar(SO₃H)_n formula where n is chosen between 1 and 2, and Ar is an aryl group containing from 6 to 12 carbon atoms . 6) Process according to claim 2 wherein the halogenated carboxylic acids have the R_x-COOH formula, where R_x is a linear, branched or cyclic alkyl group, containing at least one halogen substituent.

7) Process according to claim 6 wherein the R_x group contains from 1 to 10 carbon atoms.

8) Process according to one or more of the previous claims, wherein the acid is chosen between dodecylsulfonic acid, para-toluenesulfonic acid, 1- naphthalenesulfonic acid, 2-naphthalenesulfonic acid, 2, 5-naphthalenedisulfonic acid, 1,5- naphthalenedisulfonic acid, trifluoroacetic acid, dichloroacetic acid, trichloroacetic acid, perfluorooctanoic acid and their mixtures. 9) Process according to claim 8 wherein the acid is para-toluenesulfonic acid, 2-naphthalenesulfonic acid, 1, 5-naphthalenedisulfonic acid, or their mixtures. 10) Process according to claim 1 wherein the temperature is comprised between 160⁰C and 230⁰C.

11) Process according to claim 10 wherein the temperature is comprised between 180 and 210 ⁰C.

12) Process according to one or more of the previous claims, wherein said polysaccharide is chosen from among cellulose, hemicellulose, or their mixtures.

13) Process according to claim 12 wherein said polysaccharide is chosen from among cellulose and mixtures of hemicellulose and cellulose. 14) Process according to one or more of the previous claims, wherein said biomass is a ligno-cellulosic biomass .

15) Process according to claim 14, wherein said ligno- cellulosic biomass is chosen between: - the products of cultivations expressly cultivated for energy use, comprising refuse, residues and waste of said cultivations or their processing; the products of farm cultivations, forestation and sylviculture, comprising wood, plants, residues and refuse of farm processings, forestation and sylviculture ; - the refuse of agri-food products intended for human feeding or zootechnics; the non-chemically treated residues of the paper industry; the waste from selective solid urban waste collection.

16) Process according to any one of the previous claims, wherein said biomass is submitted to a preliminary milling process before being put in contact with said aqueous solution of at least one organic acid.

17) Process according to claim 16, wherein said biomass is milled until obtaining particles having a diameter comprised between 0.1 mm and 10 mm.

18) Process according to any one of the previous claims, wherein said biomass is present in the reaction mixture in a quantity comprised between 5% by weight and 40% by weight in relation to the total weight of the reaction mixture.

19) Process according to claim 18, wherein said biomass is present in the reaction mixture in a quantity comprised between 10% by weight and 20% by weight in relation to the total weight of the reaction mixture. 20) Process according to any one of the previous claims, wherein said at least one organic acid is water-soluble and extractable with an organic water- insoluble solvent . 21) Process according to any one of the previous claims, wherein said at least one organic acid is present in the aqueous solution at a concentration comprised between 0.1% by weight and 5% by weight in relation to the total weight of the aqueous solution. 22) Process according to claim 21, wherein said at least one organic acid is present in the aqueous solution at a concentration comprised between 0.5% by weight and 2% by weight in relation to the total weight of the aqueous solution. 23) Process according to any one of the previous claims, wherein said biomass is put in contact with said aqueous solution for a time comprised between 1 and 8 hours .

24) Process according to claim 23, wherein said biomass is put in contact with said aqueous solution for a time comprised between 2 and 5 hours .

25) Process according to any one of the previous claims, wherein said process comprises obtaining a first solid phase and a first aqueous phase. 26) Process according to claim 25, wherein said first solid phase comprises lignin. 27) Process according to claim 25, wherein said first aqueous phase comprises at least one sugar having from 5 to 6 carbon atoms and said at least one organic acid.

28) Process according to claim 27 wherein said at least one organic acid is the organic acid that is put in contact with the biomass.

29) Process according to claim 27 wherein said sugar is glucose, optionally in mixture with xylose.

30) Process according to claim 25 wherein said first aqueous phase is submitted to extraction with an organic water- insoluble solvent.

31) Process according to claim 30, wherein said organic water- insoluble solvent is chosen from among halogenated hydrocarbons, aromatic hydrocarbons and C4- C6 aliphatic alcohols and mixture of thereof. 32) Process according to claim 30 or 31 wherein said organic water- insoluble solvent is chosen between toluene and a mixture of toluene/n-butanol .

33) Process according to any one of claims from 30 to 32 wherein said organic water- insoluble solvent is evaporated obtaining a second solid phase comprising said at least one organic acid and a second aqueous phase comprising said sugar containing from 5 to 6 carbon atoms .

34) Process according to any one of the previous claims, wherein said process comprises reusing said at least one organic acid.

35) Process according to claim 33 wherein said second aqueous phase comprising at least one sugar containing from 5 to 6 carbon atoms is used directly in fermentation processes for alcohol production.

36) Biofuels obtained through the process of any one of claims from 1 to 34 followed by a fermentation stage.

37) Components that may be added to automotive fuels obtained through the process of any one of claims from 1 to 34 followed by a fermentation stage.