JP5136984B2 - Method for producing sugar - Google Patents

Description

  The present invention relates to a method for producing sugar. More specifically, the present invention relates to a sugar production method for producing sugar from woody biomass containing lignin, cellulose and hemicellulose.

  It is known that cellulose and hemicellulose can be saccharified by enzymatic degradation of woody biomass composed of cellulose, hemicellulose and lignin. The saccharide thus obtained is useful as a starting material for fuels and chemical raw materials.

  However, since woody biomass contains lignin, the lignin and cellulose and hemicellulose are entangled and tend to inhibit enzymatic degradation of cellulose and hemicellulose.

On the other hand, in recent years, a method for performing some kind of treatment before enzymatic decomposition of woody biomass to untangling lignin with cellulose and hemicellulose has been studied.
For example, after pulverizing wood, a method of enzymatically decomposing it (see, for example, Patent Document 1 or 2), a method of hydrolyzing a lignocellulose-containing plant and decomposing it (for example, Patent Document 3) See], a method in which a cellulose-containing substance is treated with a dimethylformamide solution containing nitrogen oxides, and then enzymatically decomposed (see, for example, Patent Document 4), lignocellulosic biomass is treated with pressurized hot water and mechanically pulverized. And the like (for example, refer to Patent Document 5) and the like.

On the other hand, the inventors of the present application soften the woody biomass by immersing the woody biomass in a chemical solution containing water, a water-soluble organic solvent, and an organic acid, and separate the soluble component and the insoluble component. An application has been filed for a method for producing sugar in which components are crushed and then contacted with an enzyme (see Patent Document 6).
Japanese Patent Laid-Open No. 55-9758 JP-A 63-137690 JP 59-146594 A JP 61-242591 A JP 2006-136263 A Japanese Patent Application No. 2006-279488

However, in the methods described in Patent Documents 1 and 2 described above, it is difficult to sufficiently untangling lignin with cellulose and hemicellulose.
In the methods described in Patent Documents 3 and 5, since water having a high specific heat is used at a high temperature, cellulose and hemicellulose may be excessively decomposed.
The method described in Patent Document 4 has a problem in that it is indispensable to use nitrogen oxides such as nitrogen dioxide, which is an air pollutant with environmental standards.
In the method described in Patent Document 6, pulverization is performed on the insoluble components after the cooking step, and thus a large amount of energy is required. In particular, in order to improve the saccharification rate, it is necessary to make the woody biomass about several tens of μm.

  Therefore, in the methods described in Patent Documents 1 to 6, it is difficult to obtain a high saccharification rate by a low cost and low environmental load type process because of these drawbacks.

  The present invention has been made in view of the above circumstances, and provides a method for producing sugar that can produce sugar at a sufficiently high saccharification rate under relatively mild conditions using woody biomass as a raw material. With the goal.

  When the present inventors diligently studied to solve the above problems, the present inventors diligently studied to solve the above problems, and pulverized the woody biomass and then processed it with a chemical solution for saccharification. Thus, the inventors have found that the above-described problems can be solved, and have completed the present invention.

That is, the present invention is (1) a method for producing sugar from a woody biomass containing lignin, cellulose and hemicellulose, wherein the woody biomass is pulverized to obtain a pulverized biomass having a diameter of 10 mm or less; Is immersed in a chemical solution containing water, a water-soluble organic solvent and an organic acid, and the pulverized biomass is cooked to produce micropores, the soluble components in the pulverized biomass dissolved in the chemical solution, and the insoluble in the chemical solution comprising a separation step of separating the insoluble component Do pulverized biomass, and sugar extraction step of extracting sugar from the soluble components, the saccharification step of saccharification by contacting the insoluble component to an enzyme, a cooking stage is not under inert gas atmosphere at a temperature 160 to 220 ° C., carried out under a pressure of 0.1 to 5 MPa, production water-soluble organic solvent is an alcohol der Ru sugar It resides in the law.

The present invention, (2) cooking stage is conducted in a pressure vessel, the pressure vessel is, are saturated with steam, the pressure of the pressure vessel is Ru 1-5 Baidea saturated vapor pressure above ( 1) It exists in the manufacturing method of the saccharide | sugar as described.

In the present invention, (3) the mixing ratio of water, water-soluble organic solvent and organic acid is (water: water-soluble organic solvent: organic acid), 2-79.8 mass%: 20-97.8 mass%: 0 .2～5% by mass Ru (1) consists in the manufacturing method described sugar.

This invention exists in the manufacturing method of the saccharide | sugar as described in said (1) whose compounding ratio of (4) grinding | pulverization biomass and a chemical | medical solution is 1: 1-10 by mass ratio .

  This invention exists in the manufacturing method of the saccharide | sugar as described in said (1) whose content rate of the organic acid in (5) chemical | medical solution whole quantity is 0.1 mass% or more.

  In addition, as long as the objective of this invention is met, the structure which combined said (1)-(5) suitably is also employable.

In the method for producing sugar of the present invention, lignin, cellulose, and hemicellulose are obtained by pulverizing woody biomass into pulverized biomass having a diameter of 10 mm or less and then immersing it in a chemical solution containing water, a water-soluble organic solvent, and an organic acid. Is sufficiently untangled and becomes fibrous. Moreover, micropores on the order of several tens of nm are generated in the pulverized biomass.
For this reason, the surface area of the pulverized biomass is increased, and the enzyme is easily contacted.
Then, sugar is obtained at a sufficiently high saccharification rate by bringing the cooked ground biomass into contact with the enzyme.

Further, in the above sugar production method, since a water-soluble organic solvent and an organic acid are used, it is mild compared to the case of using only water or a mineral acid such as dilute sulfuric acid or dilute hydrochloric acid and a water-soluble organic solvent. Woody biomass is treated under certain conditions.
Thereby, a high saccharification rate can be obtained by a low-cost and low environmental load type process.

  Therefore, according to the sugar production method of the present invention, it is possible to produce sugar at a sufficiently high saccharification rate even under relatively mild conditions using woody biomass as a raw material.

In the above sugar production method, since the soluble component contains a small amount of sugar, further provision of a sugar extraction step for extracting the sugar from the soluble component may increase the amount of sugar obtained. it can.
Moreover, according to this process, it is also possible to extract lignin.

In the above sugar production method, when the steaming step is performed in an inert gas atmosphere at a temperature of 160 to 220 ° C. and a pressure of 0.1 to 5 MPa, the woody biomass becomes more fibrous, and the number of ground biomass is several. Micropores on the order of 10 nm are generated.
For this reason, sugar can be manufactured with a higher saccharification rate.

In the sugar production method, when the water-soluble organic solvent is an alcohol, the entanglement between lignin, cellulose, and hemicellulose can be further solved.
In addition, since alcohol is harmless to a human body, it is excellent in safety.

  In the sugar production method, the entanglement of lignin with cellulose and hemicellulose can be reliably solved when the content ratio of the organic acid in the total amount of the chemical solution is 0.1% by mass or more.

The sugar production method according to the present embodiment includes a pulverizing step of pulverizing woody biomass to obtain a pulverized biomass having a diameter of 10 mm or less, and immersing the pulverized biomass in a chemical solution containing water, a water-soluble organic solvent, and an organic acid, Steaming the ground biomass, separating the soluble components in the ground biomass dissolved in the chemical and the insoluble components in the ground insoluble in the chemical, and saccharification by contacting the insoluble components with the enzyme A saccharification step.
Here, the woody biomass includes lignin, cellulose, and hemicellulose.

In the method for producing sugar according to the present embodiment, lignin and cellulose are obtained by pulverizing woody biomass into pulverized biomass having a diameter of 10 mm or less and then immersing it in a chemical solution containing water, a water-soluble organic solvent and an organic acid. Entangling with hemicellulose is sufficiently unwound and becomes fibrous. Moreover, micropores on the order of several tens of nm are generated in the pulverized biomass.
For this reason, the surface area of the pulverized biomass is increased, and the enzyme is easily contacted.
Then, sugar is obtained at a sufficiently high saccharification rate by bringing the cooked ground biomass into contact with the enzyme.

Further, in the above sugar production method, since a water-soluble organic solvent and an organic acid are used, it is mild compared to the case of using only water or a mineral acid such as dilute sulfuric acid or dilute hydrochloric acid and a water-soluble organic solvent. Woody biomass is treated under certain conditions.
Thereby, a high saccharification rate can be obtained by a low-cost and low environmental load type process.

  Therefore, according to the sugar production method of the present invention, it is possible to produce sugar at a sufficiently high saccharification rate even under relatively mild conditions using woody biomass as a raw material.

Hereinafter, the grinding process, the steaming process, the separation process, and the saccharification process will be described in more detail.
[Crushing process]
The pulverization step is a step of pulverizing the woody biomass to obtain a pulverized biomass having a diameter of 10 mm or less.
Thus, in the crushing step, the surface area of the woody biomass is increased by crushing the woody biomass.
If it does so, it will become easy to pulverize biomass in a chemical | medical solution in the steaming process mentioned later, and an insoluble component will become easy to contact an enzyme in the saccharification process mentioned later by extension.

  Here, the above-mentioned woody biomass refers to an organic resource derived from wood, and specifically refers to wood, rice straw, straw, bagasse, bamboo, pulp, etc. and waste paper generated from these. The pulverized biomass may be a dried product or a wet product.

  The size of the woody biomass is preferably 5 cm square or less. In this case, the woody biomass can be easily pulverized to a diameter of 10 mm or less, and the variation in the diameter distribution is reduced.

The pulverization step is performed using a pulverizer (mechanical pulverization).
Examples of such a pulverizing machine include a cutter mill, a vibration ball mill, a rotating ball mill, a planetary ball mill, a roll mill, a disk mill, a high-speed rotating blade type mixer, and a homomixer.
At this time, the diameter of the pulverized biomass obtained is 10 mm or less. In addition, it is preferable that this diameter shall be 5 mm or less.

  The pulverization is performed directly on the woody biomass. The woody biomass may be carried out in a state containing a medium such as water.

[Steaming process]
The steaming step is a step in which the pulverized biomass obtained in the pulverization step is immersed in a chemical solution containing water, a water-soluble organic solvent, and an organic acid, and the pulverized biomass is steamed.

  As described above, in the steaming step, the pulverized biomass is immersed in a chemical solution containing water, a water-soluble organic solvent, and an organic acid, so that the entanglement between lignin, cellulose, and hemicellulose is released to form a fiber. Moreover, micropores on the order of several tens of nm are generated in the pulverized biomass.

  At the same time, a part of the pulverized biomass is dissolved in the chemical solution. In addition, some of the pulverized biomass includes lignin, a trace amount of cellulose, and a degradation product of hemicellulose.

Thus, in the above-mentioned cooking step, since a water-soluble organic solvent and an organic acid are used, it is mild compared to the case of using only water or a mineral acid such as dilute sulfuric acid or dilute hydrochloric acid and a water-soluble organic solvent. The ground biomass can be steamed under certain conditions.
Therefore, decomposition of cellulose and hemicellulose can be suppressed, and the energy cost can be reduced.

  Water-soluble organic solvents include alcohols such as methanol and ethanol, polyhydric alcohols such as glycerin and ethylene glycol, and water such as aprotic polar solvents such as dimethyl sulfoxide, dimethylformamide, and N, N-dimethylacetamide. A water-soluble organic solvent having a low specific heat may be mentioned.

Among these, it is preferable that the water-soluble organic solvent is an alcohol.
In this case, the entanglement of lignin with cellulose and hemicellulose can be further solved. Moreover, since alcohols are harmless to the human body, they are excellent in safety.

Examples of the organic acid include acetic acid, oxalic acid, formic acid, succinic acid, lactic acid, malic acid, tartaric acid, and citric acid.
Among these, acetic acid, oxalic acid, formic acid and the like are preferable. Since these organic acids have a low boiling point, they can be easily removed by boiling.
In addition, there is no problem even if the organic acid remains in the saccharification step described later.

The chemical solution according to this embodiment is produced by mixing water, a water-soluble organic solvent, and an organic acid.
At this time, the mixing ratio of water, the water-soluble organic solvent and the organic acid is (water: water-soluble organic solvent: organic acid), 2-79.8% by mass: 20-97.8% by mass: 0.2-5. It is preferable that it is mass%.

When the blending ratio of the organic acid exceeds 5% by mass, the hemicellulose component may be excessively decomposed as compared with the case where the blending ratio of the organic acid is within the above range.
Moreover, when the mixing ratio of water exceeds 30% by mass, the hemicellulose component may be excessively decomposed as compared with the case where the mixing ratio of water is within the above range.

Pulverized biomass, the proportions mass ratio of the drug solution, 1: preferably 1-10.
In this case, the entanglement of lignin with cellulose and hemicellulose can be more reliably solved.

The temperature at which the pulverized biomass is immersed in the chemical solution is preferably 160 to 220 ° C.
When the temperature is lower than 160 ° C., compared to the case where the temperature is within the above range, steaming of the pulverized biomass is insufficient, so sugar tends not to be obtained at a high saccharification rate, and the temperature is 220 ° C. If the temperature exceeds the range, some sugars are decomposed as compared with the case where the temperature is within the above range, so that there is a tendency that sugars cannot be obtained at a high saccharification rate.

The steaming step is preferably performed in a pressure resistant container. The inside of the pressure vessel at this time is preferably saturated with steam, and the pressure is more preferably 1 to 5 times the saturated vapor pressure.
Specifically, the pressure in the pressure vessel is preferably 0.1 to 5 MPa.

Moreover, it is preferable that the inside of the pressure vessel is previously set in an inert gas atmosphere. Examples of the inert gas include nitrogen, argon, helium and the like.
In this case, decomposition of the pulverized biomass due to oxidation or the like is suppressed.

[Separation process]
The separation step is a step of separating the pulverized biomass soaked in the chemical solution into a soluble component in the pulverized biomass dissolved in the chemical solution and an insoluble component in the pulverized biomass insoluble in the chemical solution in the above-described cooking step.

Here, a soluble component consists of what melt | dissolved the chemical | medical solution and pulverized biomass, and an insoluble component consists of a thing insoluble in the chemical | medical solution of pulverized biomass. The insoluble component may contain a chemical solution.
Thereby, since a part of ground biomass is melt | dissolved in a chemical | medical solution, a part of lignin can be removed.

  In the separation step, a method for separating the soluble component and the insoluble component is not particularly limited, and for example, filtration or decantation is performed.

[Saccharification process]
The saccharification step is a step of saccharification by bringing an insoluble component obtained in the separation step into contact with an enzyme.

  An example of the enzyme is cellulase. By using cellulase as an enzyme, cellulose is decomposed into glucose.

The saccharification step is performed by treating a reaction solution obtained by adding an insoluble component and cellulase to a buffer solution adjusted to pH 3.5 to 5.5 with a buffering agent at a temperature of 45 to 55 ° C. for 1 to 50 hours.
Such a saccharification step may be carried out batchwise or continuously using a bioreactor containing an immobilized enzyme.

  At this time, it is preferable to use a mixture of cellulases derived from different microorganisms. In this case, saccharification of cellulose can be promoted by their synergistic effect.

As mentioned above, the saccharide | sugar obtained by the manufacturing method of the saccharide | sugar which concerns on this embodiment can be converted into ethanol by a fermentation method.
By purifying the obtained ethanol, it can be used as a raw material for chemical products, a solvent, or an automobile fuel. Moreover, the aqueous solution containing ethanol can also be used as an alcoholic beverage.
The saccharified solution can be used as a medium raw material or a carbon source for producing useful materials by biotechnology. In addition, the saccharides in the saccharified solution can be chemically converted into useful substances such as chemical products, polymer raw materials, and physiologically active substances.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

For example, you may provide the saccharide | sugar extraction process which extracts saccharide | sugar from the soluble component obtained at the isolation | separation process mentioned above.
In this case, sugar is also obtained from the soluble component, so that the amount of sugar obtained is increased.

The method for extracting the sugar is not particularly limited, and can be obtained, for example, by drying a soluble component and extracting the dried component with water.
The sugars thus obtained include oligosaccharides composed of pentoses obtained by hydrolysis of hemicellulose.
This oligosaccharide can be used as a functional food material after purification.

Moreover, according to the said sugar extraction process, it becomes possible to extract lignin.
That is, in this step, lignin that does not have a strong bond with cellulose or hemicellulose in the pulverized biomass can be separated and recovered.

  Such lignin can be separated, for example, by filtration or centrifugation, and purified by washing with water. The lignin thus obtained can be used as a film or a fiber board by, for example, compounding with a fiber or a synthetic polymer.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

Example 1
[Crushing process]
Eucalyptus wood for papermaking (2-3cm in length, 1-2cm in width, 0.5-1cm in thickness) (woody biomass) as a starting material, 2mm pass eucalyptus wood by universal cutting mill P-19 (Fritsch) This was pulverized into powder, and further pulverized biomass of 0.2 mm pass (diameter 0.2 mm) was obtained by a rotor speed mill P-14 (manufactured by Fritsch).
FIG. 1 shows a photograph of a field emission type operation electron microscope of pulverized biomass.

[Steaming process]
An autoclave (manufactured by Nitto Koatsu) made of stainless steel (SUS316) was used as the pressure vessel, and 2.19 g (dry weight 2 g) of pulverized biomass (water content 9% by weight) and ethanol (water-soluble organic) Solvent) 7.5 g, water 2.31 g, and a mixture of chemicals consisting of 0.1 g of acetic acid (organic acid) were added and sealed with a lid.

Next, nitrogen was injected into the pressure vessel to adjust the pressure in the pressure vessel to 5 MPa, and the mixture was heated to 200 ° C. over 20 minutes with stirring.
And the mixture was further stirred for 1 hour in the state which maintained the temperature in a pressure-resistant container at 200 degreeC.

[Separation process]
Thereafter, the lid was opened, and the mixture was filtered to separate into a solid (insoluble component) and a filtrate (soluble component). The obtained solid was washed with 3 ml of ethanol.
FIG. 2 shows a photograph of a field emission type operation electron microscope of the solid matter obtained.
The obtained solid had a dry weight of 1.41 g and contained 21% lignin (Klason lignin required as a component insoluble in 72% sulfuric acid).
The dry weight of the dried product obtained by drying the obtained filtrate was 0.58 g.

[Saccharification process]
60 mg (50 mg in dry weight) of the obtained solid powder was weighed into a 20 ml sample bottle, and 17 ml of 50 mM acetic acid-sodium acetate buffer (pH 5.0) and 2 mg of cellulase (Meiselase from Meiji Seika) were added. added. Then, a saccharification reaction was performed at a reaction temperature of 45 ° C. for 18 hours to obtain a saccharide-containing solution.
FIG. 3 shows a photograph of a field emission type operation electron microscope of the solid residue in the sugar-containing solution.

  On the other hand, the filtrate obtained in the separation step was dried and analyzed (sugar extraction step). The component derived from lignin was 0.35 g, and the sugar derived from hemicellulose was 0.23 g. The hemicellulose-derived sugar was a water-soluble oligosaccharide. In addition, the amount of furfural, which is a hemicellulose hyperdegradation product, was 0.4% with respect to the dry weight of the eucalyptus chip that was the starting material.

(Example 2)
In the pulverization step, a sugar-containing solution was obtained in the same manner as in Example 1 except that the eucalyptus chips for papermaking were converted into pulverized biomass of 2 mm pass (diameter 2 mm) by the universal cutting mill P-19. In the separation step, the obtained solid had a dry weight of 1.33 g and contained 22% lignin.

  On the other hand, the filtrate obtained in the separation step was dried and analyzed (sugar extraction step). The dry weight of the dried product was 0.66 g, the component derived from lignin was 0.40 g, and the sugar derived from hemicellulose was 0.25 g. In addition, the amount of furfural, which is a hemicellulose hyperdegradation product, was 0.3% with respect to the dry weight of the eucalyptus chip that was the starting material.

(Example 3)
A sugar-containing solution was obtained in the same manner as in Example 1 except that the starting raw material was paper-made bay pine chips (length: 2-3 cm, width: 1-2 cm, thickness: 0.5-1 cm). In the separation step, the dry weight of the obtained solid was 1.80 g and contained 21% lignin.

  On the other hand, the filtrate obtained in the separation step was dried and analyzed (sugar extraction step). The dry weight of the dried product was 0.20 g, the component derived from lignin was 0.14 g, and the sugar derived from hemicellulose was 0.06 g. In addition, the amount of furfural, which is a hemicellulose hyperdegradation product, was 1.5% with respect to the dry weight of the starting bay pine chip.

Example 4
Example 1 except that the starting material is bagasse produced in Okinawa (residue after squeezing sugar from sugarcane; length 1-2 cm, diameter 2-5 mm) and ground biomass of 2 mm path (diameter 2 mm) Similarly, a sugar-containing solution was obtained. In the separation step, the obtained solid had a dry weight of 1.31 g and contained 21% lignin.

  On the other hand, the filtrate obtained in the separation step was dried and analyzed (sugar extraction step). The dry weight of the dried product was 0.69 g, the component derived from lignin was 0.46 g, and the sugar derived from hemicellulose was 0.23 g. The amount of furfural, which is a hemicellulose overdecomposition product, was 0.3% with respect to the dry weight of the bagasse as the starting material.

(Example 5)
In the pulverization step, a sugar-containing solution was obtained in the same manner as in Example 1 except that the eucalyptus chip for papermaking was pulverized biomass of 10 mm path (diameter 10 mm) by the universal cutting mill P-19. In the separation step, the obtained solid had a dry weight of 1.87 g and contained 31% lignin.

  On the other hand, the filtrate obtained in the separation step was dried and analyzed (sugar extraction step). The dry weight of the dried product was 0.13 g, the component derived from lignin was 0.08 g, and the sugar derived from hemicellulose was 0.05 g. The amount of furfural, which is a hemicellulose hyperdegradation product, was 0.2% with respect to the dry weight of the eucalyptus chip that was the starting material.

(Example 6)
In the steaming step, a sugar-containing solution was obtained in the same manner as in Example 1 except that ethylene glycol (water-soluble organic solvent) was used instead of ethanol. In the separation step, the obtained solid had a dry weight of 1.27 g and contained 23% lignin.

  On the other hand, the filtrate obtained in the separation step was dried and analyzed (sugar extraction step). The dry weight of the dried product was 0.73 g, the component derived from lignin was 0.45 g, and the sugar derived from hemicellulose was 0.28 g. In addition, the amount of furfural, which is a hemicellulose hyperdegradation product, was 0.5% with respect to the dry weight of the eucalyptus chip that was the starting material.

(Example 7)
Same as Example 1 except that in the steaming process, a mixture consisting of 5 g of ethanol (water-soluble organic solvent), 4.81 g of water and 0.1 g of acetic acid (organic acid) was used, and the pressure in the pressure vessel was adjusted to 2 MPa. Thus, a sugar-containing solution was obtained. In the separation step, the obtained solid had a dry weight of 1.27 g and contained 26% lignin.

  On the other hand, the filtrate obtained in the separation step was dried and analyzed (sugar extraction step). The dry weight of the dried product was 0.73 g, the component derived from lignin was 0.49 g, and the sugar derived from hemicellulose was 0.24 g. In addition, the amount of furfural, which is a hemicellulose hyperdegradation product, was 1.4% with respect to the dry weight of the eucalyptus chip that was the starting material.

(Example 8)
In the steaming step, a sugar-containing solution was obtained in the same manner as in Example 7 except that the pressure in the pressure vessel was adjusted to 0.5 MPa. In the separation step, the obtained solid had a dry weight of 1.28 g and contained 39% lignin.

  On the other hand, the filtrate obtained in the separation step was dried and analyzed (sugar extraction step). The dry weight of the dried product was 0.50 g, the component derived from lignin was 0.29 g, and the sugar derived from hemicellulose was 0.20 g. In addition, the amount of furfural, which is a hemicellulose hyperdegradation product, was 1.2% with respect to the dry weight of the eucalyptus chip that was the starting material.

Example 9
Example 1 except that in the steaming step, a mixture of 2.5 g of ethanol (water-soluble organic solvent), 7.31 g of water and 0.1 g of acetic acid (organic acid) was used, and the pressure in the pressure vessel was adjusted to 2 MPa. In the same manner as above, a sugar-containing solution was obtained. In the separation step, the obtained solid had a dry weight of 1.68 g and contained 28% lignin.

  On the other hand, the filtrate obtained in the separation step was dried and analyzed (sugar extraction step). The dry weight of the dried product was 0.32 g, the component derived from lignin was 0.09 g, and the sugar derived from hemicellulose was 0.23 g. In addition, the amount of furfural, which is a hemicellulose hyperdegradation product, was 3.7% with respect to the dry weight of the eucalyptus chip that was the starting material.

(Example 10)
In the steaming step, a sugar-containing solution was obtained in the same manner as in Example 9 except that the pressure in the pressure vessel was adjusted to 0.5 MPa. In the separation step, the obtained solid had a dry weight of 1.69 g and contained 29% lignin.

  On the other hand, the filtrate obtained in the separation step was dried and analyzed (sugar extraction step). The dry weight of the dried product was 0.31 g, the component derived from lignin was 0.10 g, and the sugar derived from hemicellulose was 0.21 g. In addition, the amount of furfural, which is a hemicellulose hyperdegradation product, was 0.9% with respect to the dry weight of the eucalyptus chip that was the starting material.

(Example 11)
In the steaming step, a sugar-containing solution was obtained in the same manner as in Example 10 except that the temperature in the pressure vessel was adjusted to 180 ° C. In the separation step, the obtained solid had a dry weight of 1.70 g and contained 29% lignin.

  On the other hand, the filtrate obtained in the separation step was dried and analyzed (sugar extraction step). The dry weight of the dried product was 0.30 g, the component derived from lignin was 0.08 g, and the sugar derived from hemicellulose was 0.22 g. In addition, the amount of furfural, which is a hemicellulose hyperdegradation product, was 3.7% with respect to the dry weight of the eucalyptus chip that was the starting material.

(Example 12)
In the steaming step, a chemical solution consisting of 5.48 g (dry weight 5 g) of pulverized biomass (water content 9% by weight), 2.5 g of ethanol (water-soluble organic solvent), 7.03 g of water and 0.1 g of acetic acid (organic acid) A sugar-containing solution was obtained in the same manner as in Example 10 except that a mixture obtained by mixing with was used. In the separation step, the obtained solid had a dry weight of 4.59 g and contained 28% lignin.

  On the other hand, the filtrate obtained in the separation step was dried and analyzed (sugar extraction step). The dry weight of the dried product was 0.41 g, the component derived from lignin was 0.03 g, and the sugar derived from hemicellulose was 0.39 g. In addition, the amount of furfural, which is a hemicellulose hyperdegradation product, was 0.98% with respect to the dry weight of the eucalyptus chip that was the starting material.

(Example 13)
In the pulverization step, the eucalyptus chips for papermaking are converted into pulverized biomass of 5 mm pass (diameter 5 mm) by the universal cutting mill P-19, and in the steaming step, 3.65 g of pulverized biomass (water content 9% by weight) (dry weight 3.3 g) ), 2.5 g of ethanol (water-soluble organic solvent), 7.18 g of water and 0.1 g of acetic acid (organic acid) 0.1 g. A containing solution was obtained. In the separation step, the obtained solid had a dry weight of 3.14 g and contained 29% lignin.

  On the other hand, the filtrate obtained in the separation step was dried and analyzed (sugar extraction step). The dry weight of the dried product was 0.19 g, the component derived from lignin was 0.19 g, and the sugar derived from hemicellulose was 0.01 g. In addition, the amount of furfural, which is a hemicellulose hyperdegradation product, was 1.63% with respect to the dry weight of the eucalyptus chip that was the starting material.

(Example 14)
The starting material is a bay pine chip for papermaking (length 2-3 cm, width 1-2 cm, thickness 0.5-1 cm), ethanol (water-soluble organic solvent) 5 g, water 4.81 g and acetic acid (organic acid) 0.1 g A sugar-containing solution was obtained in the same manner as in Example 1 except that the mixture consisting of In the separation step, the dry weight of the obtained solid was 1.35 g and contained 26% lignin.

  On the other hand, the filtrate obtained in the separation step was dried and analyzed (sugar extraction step). The dry weight of the dried product was 0.65 g, the component derived from lignin was 0.37 g, and the sugar derived from hemicellulose was 0.28 g. In addition, the amount of furfural, which is a hemicellulose hyperdegradation product, was 1.6% with respect to the dry weight of the eucalyptus chip that was the starting material.

(Example 15)
The starting material is a bay pine chip for papermaking (length 2-3 cm, width 1-2 cm, thickness 0.5-1 cm), ethanol (water-soluble organic solvent) 2.5 g, water 7.31 g and acetic acid (organic acid) 0 A sugar-containing solution was obtained in the same manner as in Example 1 except that a mixture consisting of 0.1 g was used. In the separation step, the obtained solid had a dry weight of 1.66 g and contained 33% lignin.

  On the other hand, the filtrate obtained in the separation step was dried and analyzed (sugar extraction step). The dry weight of the dried product was 0.34 g, the component derived from lignin was 0.08 g, and the sugar derived from hemicellulose was 0.26 g. In addition, the amount of furfural, which is a hemicellulose hyperdegradation product, was 1.2% with respect to the dry weight of the eucalyptus chip that was the starting material.

(Example 16)
In the pulverization step, a saccharide-containing solution was obtained in the same manner as in Example 14 except that the hinoki chips were pulverized biomass of 2 mm path (diameter 2 mm) by the universal cutting mill P-19, and this was used as a starting material. In the separation step, the obtained solid had a dry weight of 1.57 g and contained 33% lignin.

  On the other hand, the filtrate obtained in the separation step was dried and analyzed (sugar extraction step). The dry weight of the dried product was 0.43 g, the component derived from lignin was 0.30 g, and the sugar derived from hemicellulose was 0.13 g. In addition, the amount of furfural, which is a hemicellulose hyperdegradation product, was 0.5% with respect to the dry weight of the eucalyptus chip that was the starting material.

(Comparative Example 1)
In the pulverization step, a sugar-containing solution was obtained in the same manner as in Example 1 except that the eucalyptus chips for papermaking were converted into pulverized biomass of 15 mm path (diameter 15 mm) by the universal cutting mill P-19. In the separation step, the dry weight of the obtained solid was 1.87 g and contained 32% lignin.

  On the other hand, the filtrate obtained in the separation step was dried and analyzed (sugar extraction step). The dry weight of the dried product was 0.13 g, the component derived from lignin was 0.03 g, and the sugar derived from hemicellulose was 0.1 g. In addition, the amount of furfural, which is a hemicellulose hyperdegradation product, was 0.3% with respect to the dry weight of the eucalyptus chip that was the starting material.

(Comparative Example 2)
In the steaming step, a sugar-containing solution was obtained in the same manner as in Example 1 except that ethanol (water-soluble organic solvent) was not used. In the separation step, the obtained solid had a dry weight of 0.64 g and contained 69% of a component insoluble in 72% sulfuric acid. This is because the solid was burnt.

  On the other hand, the filtrate obtained in the separation step was dried and analyzed (sugar extraction step). The dry weight of the dried product was 1.40 g, the component derived from lignin was 0.47 g, and the sugar derived from hemicellulose was 0.93 g. In addition, the amount of furfural, which is a hemicellulose hyperdegradation product, was 1.8% with respect to the dry weight of the eucalyptus chip that was the starting material.

(Comparative Example 3)
In the steaming step, a sugar-containing solution was obtained in the same manner as in Example 1 except that acetic acid (organic acid) was not used. In the separation step, the obtained solid had a dry weight of 1.52 g and contained 31% lignin.

  On the other hand, the filtrate obtained in the separation step was dried and analyzed (sugar extraction step). The dry weight of the dried product was 0.47 g, the component derived from lignin was 0.28 g, and the sugar derived from hemicellulose was 0.19 g. In addition, the amount of furfural, which is a hemicellulose hyperdegradation product, was 0.3% with respect to the dry weight of the eucalyptus chip that was the starting material.

(Comparative Example 4)
Eucalyptus wood for papermaking (2-3 cm in length, 1-2 cm in width, 0.5-1 cm in thickness) (woody biomass) as a starting material, 2 mm pass eucalyptus wood by universal cutting mill P-19 (Fritsch) The powder was pulverized, and further pulverized biomass of 0.2 mm (diameter 0.2 mm) pass was obtained by a rotor speed mill P-14 (manufactured by Fritsch).

  60 mg of this pulverized biomass was weighed into a 20-ml sample bottle, and 17 ml of 50 mM acetic acid-sodium acetate buffer (pH 5.0) and 2 mg of cellulase (Meiji Seika Mecellase) were added. Then, a saccharification reaction was performed at a reaction temperature of 45 ° C. for 18 hours to obtain a saccharide-containing solution.

(Comparative Example 5)
Comparative Example 4 with the exception that the starting material was paper-made bay pine chips (length: 2-3 cm, width: 1-2 cm, thickness: 0.5-1 cm), and ground biomass of 0.2 mm path (diameter: 0.2 mm) Similarly, a sugar-containing solution was obtained.

(Comparative Example 6)
Comparative Example 4 with the exception that the starting material was bagasse produced in Okinawa (residue after squeezing sugar from sugarcane; length 1-2 cm, diameter 2-5 mm) and crushed biomass of 2 mm path (diameter 2 mm) Similarly, a sugar-containing solution was obtained.

[Evaluation method]
In each of Examples 1 to 16 and Comparative Examples 1 to 6, the resulting sugar-containing solution was taken out over time, and it was subjected to solid-liquid separation by centrifugation (2500 rpm, 10 minutes), and the amount of glucose contained in the solution was determined as Aminex. The saccharification rate was calculated by measurement with a high-performance liquid chromatography LC-2000Plus manufactured by JASCO Corporation equipped with an HPX-87P column (manufactured by Bio-Rad).
The obtained results (saccharification rate) are shown in Table 1. The saccharification rate means the ratio of the saccharified component (glucose amount) to the content of the cellulose component in the raw material (woody biomass).

  As is clear from the results shown in Table 1, according to the method for producing sugars of Examples 1 to 16, compared with the methods of Comparative Examples 1 to 6, the pulverized biomass can be saccharified at a sufficiently high saccharification rate. all right.

  In addition, as shown in FIG. 1, the surface of the pulverized biomass of eucalyptus that has been milled by the cutter is smooth, but after passing through the steaming step, micropores on the order of several tens of nm are generated on the surface, as shown in FIG. Furthermore, after enzymatic saccharification, as shown in FIG. 3, it was found that micropores on the order of several hundred nm were generated.

  By this, the lignin and hemicellulose components in the biomass are desorbed by steaming, and micropores on the order of several tens of nanometers are generated. Therefore, the surface area is increased and the enzyme is likely to come into contact. In addition, the cellulose component is converted to glucose by enzymatic saccharification, becomes water-soluble, and is desorbed. Therefore, it is considered that the diameter of the micropores increases.

  From the above, according to the present invention, it was confirmed that sugar can be produced at a sufficiently high saccharification rate even under relatively mild conditions using woody biomass as a raw material.

1 is a photograph of a field emission type operation electron microscope of the pulverized biomass obtained in Example 1. FIG. FIG. 2 is a photograph of a field emission type operation electron microscope of the solid material obtained in Example 1. FIG. 3 is a photograph of a field emission type operation electron microscope of the solid residue in the sugar-containing solution obtained in Example 1.

Claims (5)

A method for producing sugar from woody biomass containing lignin, cellulose and hemicellulose,
Crushing the woody biomass to a pulverized biomass having a diameter of 10 mm or less;
A steaming step in which the pulverized biomass is immersed in a chemical solution containing water, a water-soluble organic solvent and an organic acid, and the pulverized biomass is steamed to generate micropores ;
A separation step of separating a soluble component in the pulverized biomass dissolved in the chemical liquid and an insoluble component in the pulverized biomass insoluble in the chemical liquid;
A sugar extraction step of extracting sugar from the soluble component;
A saccharification step in which the insoluble component is saccharified by contacting with an enzyme;
Equipped with a,
The steaming step is performed under an inert gas atmosphere at a temperature of 160 to 220 ° C. and a pressure of 0.1 to 5 MPa.
Method for producing a sugar wherein the water-soluble organic solvent, wherein the alcohol der Rukoto. The steaming process is performed in a pressure vessel,
The inside of the pressure vessel is saturated with steam,
The process according to claim 1, wherein sugars pressure of the pressure vessel is characterized by 1-5 Baidea Rukoto saturated vapor pressure. The mixing ratio of the water, the water-soluble organic solvent and the organic acid is (water: water-soluble organic solvent: organic acid), 2-79.8% by mass: 20-97.8% by mass: 0.2-5. the process according to claim 1, wherein the saccharide, wherein% by mass Rukoto. The method for producing sugar according to claim 1 , wherein a mixing ratio of the pulverized biomass and the chemical solution is 1: 1 to 10 in terms of mass ratio .   The method for producing sugar according to claim 1, wherein the content ratio of the organic acid in the total amount of the chemical solution is 0.1% by mass or more.

Images