JPS5858079B2 - Cellulose saccharification method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for treating a cellulose-containing material to produce sugar from the cellulose-containing material using cellulase.

In recent years, research has been actively conducted to produce glucose by saccharifying cellulose in order to produce alcohols as an alternative fuel and to secure food resources.

In nature, cellulose exists tightly bound to lignin and hemicellulose, so it is difficult to be degraded by cellulases as it is.

Therefore, various methods have been devised to remove lignin and hemicellulose or to destroy the crystal structure of cellulose in order to make it more susceptible to decomposition by cellulase.

For example, chemical methods that delignify and dehemicellulose cellulose-containing materials with acids or alkalis, destroy the crystal structure of cellulose, and physical methods that pulverize cells until they can be decomposed by cellulase are known. .

The present inventor has conducted various studies on pretreatment methods for cellulose-containing materials with the aim of producing carbohydrates from cellulose-containing materials using cellulase. As a result, the present inventors have discovered that cellulose-containing materials are heated to a foaming temperature in the presence of a foaming agent. Then, the saccharification by cellulase is significantly improved, and
It was found that a saccharified product with a high glucose content can be obtained, and the present invention was completed.

That is, since the pretreatment method for cellulose-containing materials according to the method of the present invention is carried out under relatively mild conditions where the pH is weakly acidic to weakly alkaline, there is little decomposition and extraction of hemicellulose and lignin.

Therefore, the sugar obtained by saccharifying the processed product according to the present invention with cellulase is lower than that obtained by conventionally processing using caustic soda or acid under strongly alkaline or strongly acidic conditions.
The content of glycose in the saccharide is high.

In other words, it was found that the proportion of constituent sugars derived from hemicellulose such as xylose can be kept low.

The present invention has been made based on this knowledge.

That is, the present invention relates to a method for treating a cellulose-containing material, which comprises heating the cellulose-containing material to a foaming temperature in the presence of a foaming agent when producing sugar by saccharifying the cellulose-containing material with cellulase. It is.

Cellulose-containing substances to which the present invention can be applied are woody or non-woody (plants) plants or derivatives thereof,
Examples include agricultural waste such as rice straw, wheat straw, rice husk, and bagasse, weeds such as navy and cogon, wood, pulp, waste paper, and senile waste.

These do not need to be completely delignified, but depending on the type of cellulose-containing material, it is desirable that they be lightly chemically treated or pulverized to the extent that they can be penetrated by a blowing agent.

Further, in order to improve the permeability of the blowing agent, the cellulose-containing material is desirably dried to a water content of 50% or less, preferably 20% or less.

The blowing agents used in the present invention include, for example, inorganic ones such as sodium bicarbonate, ammonium carbonate, or those containing these, and examples of organic blowing agents such as sulfohydrazide foaming agents. Examples of the blowing agent include benzenesulfonylhydrazide (BSH), P-toluenesulfonylhydrazide (TSH), and P-P'-oxybenzenesulfonylhydrazide, and examples of the nitroso blowing agent include dinitrosopentamethylenetetramine (DPT or DNPT). , N, N'-dimethyl N, N'
Examples include dinitrosoterephthalamide, etc. Ab-based blowing agents include azobisisobutyronitrile (ABN).
, abdicarbonamide (AC), etc., but those that are water-soluble or soluble in organic solvents such as alcohol are particularly desirable.

The blowing agent is dissolved in water or an organic solvent, or is emulsified and suspended, and then immersed in and permeated into the cellulose-containing material.

When the foaming agent is heated to the foaming temperature, it generates carbon dioxide gas, nitrogen gas, carbon monoxide gas, etc., and the pressure generated during this generation treats the structure of the cellulose-containing material so that cellulase is more likely to react with it.

The foaming temperature varies depending on the type of foaming agent, but is usually 50 to 200°C.

However, the foaming temperature can be lowered by the presence of urea, an organic acid, or a metal salt, and is usually carried out at a temperature of 50 to 150°C.

Using various surfactants to infiltrate the foaming agent into the cellulase-containing material improves the permeability of the foaming agent.
Therefore, it can be penetrated in a short time.

In addition, the surfactant also improves the subsequent reactivity with cellulase.

As surfactants, in particular derivatives of polyethylene glycol, such as Triton x-ioo1 Triton X-4
05 (all manufactured by Rohm and Haas, USA, trade name of polyoxyethylene glycol P-inoctylphenyl ether), Tween 20 (polyoxyethylene (2-cho norbitan monolaurate), Tween 40 (polyoxyethylene (2-cho norbitan monolaurate)), 20) Sorbitan monopalmitate), Tween 60 (polyoxyethylene (
20) Sorbitan monostearate), Tween 80 (
polyoxyethylene (20) sorbitan monooleate), Tween 85 (polyoxyethylene (20) sorbitan trioleate) (all of the above are American,
A nonionic surfactant manufactured by Atlas Powder Co., Ltd.) is used, and these surfactants are usually used in an amount of about 0.01 to 1%.

Treatment of cellulose-containing materials with a blowing agent usually involves immersing the cellulose-containing material in a solution or emulsified suspension of the blowing agent.
It can also be carried out by a batch method in which the cellulose-containing material is thoroughly penetrated into the tissue and then heated to the foaming temperature, but if an extrusion type continuous heating foaming treatment device is used, a large amount of cellulose-containing materials can be treated. Not only is this possible, but the cellulose-containing material can reach the foaming temperature rapidly and in a short period of time, resulting in a remarkable tissue destruction effect.

Therefore, it is possible to obtain a treated product that is highly degradable by cellulase.

After treating a cellulose-containing material with a foaming agent, it may be directly saccharified with cellulase, but a saccharified solution with fewer impurities can be obtained by washing the treated material with an aqueous alkaline solution or alcohol, and then using it. .

Next, the present invention will be explained in detail with reference to Examples.

Example 1 50 mg each of bagasse (0.5 m 7 m ) was added to 1 liter of distilled water.
rnlO 15% sodium bicarbonate solution 0.5 TLl or 1
% sodium bicarbonate solution, 0.1% amount of Triton

After cooling this treated material, add 0.5 ru of 0.2M acetate buffer.
1, adjust the pH to about 5, and add Trichoderma cellulase enzyme preparation (manufactured and sold by Yakult Biochemical Co., Ltd., Cellulase, Onozuka R-10) and Aspergillus cellulase enzyme preparation (manufactured and sold by Nagase Biochemical Co., Ltd.). 5 each
: Add 12 units of mixed enzyme solution of 1 to bring the total volume to 21 rLl.
The reaction was carried out at 45°C.

After the completion of saccharification, the filtered supernatant was quantified for reducing sugars by the Somogyy-Nelson method, soluble sugars (total sugars) by the phenol sulfuric acid method, and glucose amount by the glucose oxidase method.

The results obtained are shown in Table 1.

As is clear from the table, by treating bagasse with sodium bicarbonate, it was possible to recover soluble sugars with a yield of about 50 to about 60%.

Example 2 5077f each of bagasse (0.5m/m2) and 1m of distilled water
l or 1% P-toluenesulfonyl hydrazide (TS
H) Place 0.1 m of Triton X-405 in each.
After adding 1% amount and allowing sufficient penetration, heat treatment was performed at 120° C. for 20 minutes in an autoclave.

After cooling the treated material, add 0.2M acetate buffer 0.5-p
H was adjusted to about 5, the same enzyme solution used in Example 1 was added, and the reaction was carried out at 45°C.

After the reaction, the reducing sugar, total sugar, and glucose amounts of the filtered supernatant were determined.

The results obtained are shown in Table 2.

As is clear from the table, by treatment in the presence of TSH, the production amounts of reducing sugars, soluble sugars, and glucose significantly increased.

Example 3 To 500 m of bagasse (approximately 0.5 m/m), 5 ml of 1% P-toluenesulfonyl hydrazide (TSH) and 1%
5 ml of Triton

The results obtained are shown in Table 3.

As is clear from the table, reducing sugars, soluble sugars, and glucose all increased significantly in the TSH-treated samples compared to the untreated samples.

Example 4 In Example 1, instead of sodium bicarbonate, 1%, 2
．． After heat treatment was performed in the same manner using 5% or 5% ammonium carbonate, the mixture was saccharified with cellulase at 45° C. for 2 days.

After saccharification, reducing sugars and soluble sugars were quantified in the filtrate.

The results obtained are shown in Table 4.

By heat treatment in the presence of ammonium carbonate,
The yield of sugar increased by about 30-40%.

Example 5 In Example 1, instead of bagasse, about 0.5 m 7 m
Using 50 pieces of crushed straw, 1% sodium bicarbonate IJ
treated with um.

The results obtained are shown in Table 5.

Example 6 Table 6 shows the results obtained by using NKP pulp (Douglas fir) containing about 5% lignin in place of bagasse in Example 1.

As is clear from the table, both reducing sugar and soluble sugar significantly increased by heat treatment with ammonium carbonate or sodium bicarbonate.

Claims (1)

[Claims] 1. A method for treating a cellulose-containing material, which comprises heating the cellulose-containing material to a foaming temperature in the presence of a foaming agent when producing sugar by saccharifying the cellulose-containing material with cellulase.