JP2007074992A - Method for saccharifying biomass containing cellulose and saccharide given by the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for saccharifying cellulose, capable of efficiently conducting hydrolysis, even when biomass containing the cellulose is not fine granular, and capable of giving a high yield of a saccharide, and to provide the saccharide given by the method for saccharifying. <P>SOLUTION: This method for saccharifying the cellulose comprises hydrolyzing and saccharifying the cellulose contained in the biomass by using an enzyme, wherein hydrothermal treatment is conducted by using hydrogen peroxide in a previous step in which the hydrolysis is conducted by using the enzyme, so that lignin contained therein is decomposed and removed. When the hydrothermal treatment is conducted by using the hydrogen peroxide and aluminum phosphate, an effect thereof is more enhanced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for saccharification of cellulose contained in wood chips, and more particularly to a method for saccharification of cellulose in which biomass is hydrothermally treated with hydrogen peroxide and the resulting sugar.

Technologies for effectively using so-called biomass such as wood chips, wood chips, rice straw and rice husks have been developed.
Techniques for producing various substances using cellulose, which is a component of these biomasses, as starting materials are provided.
In particular, with the recent demand for alcohol fermentation technology, a technology for producing sugars (glucose, xylooligosaccharide, cellooligosaccharide, xylose, etc.) in particular from biomass is required.

Among these techniques, for example, as a method for saccharifying cellulose, there is a method using acetic anhydride or concentrated sulfuric acid.
However, these methods require a drying step, and the hydrolysis is also performed vigorously, so that the equipment of the reaction system becomes complicated.
Furthermore, corrosion due to acid is likely to occur in the facility, and extra cost is required for sulfuric acid recovery.
Enzymatic methods capable of performing hydrolysis under mild conditions have been developed as means for solving these problems.

This method hydrolyzes using an enzyme (for example, cellulase), and does not require a pressure-resistant and acid-resistant reaction vessel in the apparatus, and also has little environmental pollution.
Examples of saccharification methods using such enzymes include Patent Document 1 and Patent Document 2.

JP 2001-95594 A JP-A-8-308589

However, in general, lignin is glued to cellulose, and this lignin greatly reduces the hydrolysis efficiency of cellulose and makes the saccharification rate extremely low.
In addition, there is a lignin removal method (Japanese Patent Application No. 2004-333445) that we invented as a method for removing lignin. However, this method has a problem that the effect is not exhibited unless the biomass is finely granular,
The present invention has been made based on such a technical background.
That is, the present invention provides a method for saccharification of cellulose that can be efficiently hydrolyzed even if the biomass containing cellulose is not fine particles and has a high sugar yield.
Moreover, the sugar obtained by the saccharification method is provided.

  Therefore, as a result of intensive studies on the above problems, the present inventor performed a hydrothermal treatment with hydrogen peroxide before the saccharification treatment with the enzyme, thereby smoothly decomposing and removing lignin that hinders saccharification by the enzyme. I found it possible.

  That is, the present invention is (1) a method for hydrolyzing and saccharifying cellulose contained in biomass using an enzyme, and performing hydrothermal treatment using hydrogen peroxide at a stage prior to hydrolysis using the enzyme. This is a method for saccharifying cellulose by decomposing and removing lignin contained therein.

    Moreover, this invention exists in the saccharification method of the cellulose of the said (1) description which hydrothermally treats with (2) hydrogen peroxide water and aluminum phosphate.

  The present invention also resides in (3) the method for saccharifying cellulose according to (1) above, wherein the enzyme is cellulase.

  Moreover, this invention exists in the saccharification method of the cellulose of the said (1) description which performed ozone treatment to (4) the hot-water process using hydrogen peroxide water.

  Moreover, this invention exists in the saccharification method of the cellulose as described in said (1) whose (5) and biomass are small pieces.

  Moreover, this invention exists in the saccharide | sugar manufactured by the saccharification method of at least 1 description of (6) and said (1)-(4).

  In the present invention, (7), the sugar is glucose, fructose, or mannose.

  In addition, as long as the objective of this invention is followed, the structure which combined two or more selected from said (1)-(5) is also employable.

Cellulose is heated at a high temperature for a certain period of time using hydrogen peroxide water to decompose and lyse lignin from cellulose in advance, and then enzymatically saccharify to efficiently perform hydrolysis, thereby greatly improving the yield of sugar.
In addition, the hydrothermal treatment using hydrogen peroxide can recover sugar with a higher yield than the ozone treatment.
In addition, unlike the case of ozone treatment, the effect can be exhibited even if the biomass is small pieces (size: about 1 cm to 10 cm) if hydrothermal treatment with hydrogen peroxide is performed.
Therefore, the energy required for the work of granulating the wood pieces and the like up to now becomes unnecessary, and the energy efficiency when producing monosaccharides from biomass, that is, cellulose can be improved.

The present invention is characterized by decomposing cellulose lignin by hydrothermal treatment with water first added with hydrogen peroxide in the process of degrading and saccharifying cellulose using an enzyme. .
Hereinafter, the saccharification step of the saccharification method of cellulose will be described based on the flowchart of FIG.

[Hot water treatment with hydrogen peroxide]
A piece of wood crushed to an appropriate size is usually heated with hydrogen peroxide water at 210 ° C. to 275 ° C. for about 30 seconds to 10 minutes.
By applying this treatment to the wood pieces, the lignin glued to the cellulose can be decomposed and leached from the cellulose.

[Ozone treatment]
When performing the ozone treatment, the hot-water-treated liquid is suspended in a container containing distilled water, and ozone gas is injected into the container by an air diffuser method, and the treatment is performed for 1 to 3 hours.

[Enzymatic saccharification treatment of cellulose]
After cooling the hydrothermally treated solution, an appropriate amount of cellulase, which is a hydrolyzing enzyme of cellulose, is added and left for a certain period of time until the reaction is completed.
The solution is filtered to obtain sugar (solute).
The recovered sugar is mainly glucose, and fructose and mannose are also recovered.
In addition, from the viewpoint of causing the enzyme to act most effectively, the saccharification is preferably performed at 30 ° C. to 50 ° C., pH 3 to 4.5, and a reaction time of 24 hours or more.

[Hot water treatment with aluminum phosphate]
Even with hydrothermal treatment using the above hydrogen peroxide solution, lignin can be sufficiently decomposed and leached from cellulose, but by hydrothermal treatment with aluminum phosphate and hydrogen peroxide solution, The lignin is reliably decomposed and the yield is greatly improved.

[Example 1]
A piece of wood (cedar is used in this experiment) is made into a small piece of about 2 cm square and used as a sample.
12 ml of a reaction solution is prepared by mixing the sample, hydrogen peroxide solution (31 wt%) and water (sample: 100 mg, hydrogen peroxide solution: 0.1 ml).
The reaction solution is put into a hydrothermal reaction vessel (internal volume 14 ml, made of stainless steel) and subjected to hot water treatment at 245 ° C. for 6 minutes.
After the hydrothermal treatment, cellulase (cellulosin T2: trade name of HIB), which is a hydrolase, was added at a rate of 3 mg with respect to 12 ml of the hydrothermally treated solution to perform enzymatic saccharification of cellulose. The processing conditions for the enzymatic saccharification treatment were a temperature of 50 ° C., a pH of 4.5, and a reaction time of 24 hours.
For analysis of the produced sugar, an ion chromatograph (manufactured by DIONEX) was used. As a result, glucose, fructose, and mannose were detected as sugars and recovered.

[Example 2]
All procedures were the same as in Example 1 except that 0.5 ml of hydrogen peroxide solution, hot water temperature of 225 ° C., and hot water treatment time were 10 minutes.

[Comparative Example 1]
All procedures were the same as in Example 1 except that the hydrogen peroxide solution was 0 ml, the hot water temperature was 265 ° C., and the hot water treatment time was 5 minutes.
As described above, the sugar detected in Example 2 and Comparative Example 1 was mainly glucose as in Example 1, and fructose and mannose were also detected.
In addition, the amounts of glucose collected from the results of Examples and Comparative Examples were converted into the amount collected per 1 g of the sample, and the results are shown in Table 1.

  From the experimental results, it was confirmed that the amount of glucose produced by the hot water treatment greatly increased.

[Table 1]

[Comparative Example 2]
All procedures were the same as in Example 1, except that the hydrogen peroxide solution was 0 ml, the hot water treatment time was 3 minutes, and the ozone treatment time was 1 hour.
The sugar detected in Comparative Example 2 was mainly glucose as in Example 1, and in addition, fructose and mannose were detected.
The amount of glucose recovered in Comparative Example 2 is converted to the amount recovered per gram of sample, and the results are shown in Table 2 in comparison with Example 1.

  From the experimental results shown in Table 2, it was found that hydrothermal treatment with hydrogen peroxide was more effective than ozone treatment for the decomposition of lignin.

[Table 2]

Example 3
All procedures were performed in the same manner as in Example 1 except that the hydrothermal treatment time was 5 minutes and then the ozone treatment was performed for 1 hour.
The sugar detected in Example 3 was mainly glucose as in Example 1, and fructose and mannose were also detected.
The amount of glucose recovered in Example 3 is converted to the amount recovered per gram of sample, and the results are shown in Table 3 in comparison with Example 1.

  From the results in Table 3, it was found that a synergistic effect was exhibited by combining hot water treatment and ozone treatment, and lignin could be decomposed more reliably and efficiently recovered.

[Table 3]

Example 4
The same procedure as in Example 1 was performed except that 14.5 mg of aluminum phosphate was added to the hydrogen peroxide solution, the hot water temperature was 265 ° C., and the hot water treatment time was 2 minutes.
The sugar detected in Example 4 was mainly glucose as in Example 1, and fructose and mannose were also detected.
The amount of glucose recovered in Example 4 is converted to the amount recovered per gram of sample, and the results are shown in Table 4 in comparison with Example 1.

  According to the experimental results in Table 4, the synergistic effect when hydrothermal treatment is performed using hydrogen peroxide and aluminum phosphate rather than the synergistic effect when ozone treatment and hydrothermal treatment with hydrogen peroxide are used together Was found to exhibit a greater effect and to collect a larger amount of glucose.

[Table 4]

The present invention has been described above. However, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the essence thereof.
For example, it is naturally possible to carry out by changing the hot water treatment time, the amount of hydrogen peroxide solution added, the concentration of hydrogen peroxide solution, and the like.

FIG. 1 is a flowchart showing a biomass saccharification process.

Claims (7)

  This is a method of hydrolyzing and saccharifying cellulose contained in biomass using an enzyme, and hydrothermal treatment using hydrogen peroxide is performed before hydrolyzing using an enzyme to decompose lignin contained in the hydrolyzed cellulose. A method for saccharifying cellulose, which comprises removing the cellulose.   2. The method for saccharifying cellulose according to claim 1, wherein hydrothermal treatment is performed with hydrogen peroxide water and aluminum phosphate.   The method for saccharifying cellulose according to claim 1, wherein the enzyme is cellulase.   The method for saccharification of cellulose according to claim 1, wherein ozone treatment is further performed on the hot water treatment using hydrogen peroxide water.   The method for saccharifying cellulose according to claim 1, wherein the biomass is in the form of small pieces.   The sugar manufactured by the saccharification method of at least 1 of the said Claims 1-4.   The sugar according to claim 6, wherein the sugar is glucose, fructose, or mannose.

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