JPH05317073A - Production of cellooligosaccharide - Google Patents

Abstract

PURPOSE:To easily obtain a cellooligosaccharide at a low cost by hydrolyzing a cellulose raw material rich in amorphous cellulose with cellulase in the presence of lignin while suppressing the inhibition of the hydrolysis reaction by a specific method. CONSTITUTION:A cellulose raw material rich in amorphous cellulose is hydrolyzed with cellulase in the presence of lignin. beta-Glucosidase in the cellulase is adsorbed to lignin and inactivated by this process to effect the formation of cellooligosaccharide in high selectivity. The inhibition of the hydrolysis reaction of cellulase with cellobiose can be suppressed by arbitrarily separating at least cellobiose in the cellooligosaccharide obtained by the hydrolysis reaction from the reaction liquid. The cellulose raw material is e.g. unbleached pulp containing amorphous cellulose and lignin.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing cellooligosaccharides such as cellobiose.

[0002]

2. Description of the Related Art Cello-oligosaccharides such as cellobiose, cellotriose, and cellotetraose have been known as diet sweeteners. This cellooligosaccharide is generally obtained by hydrolyzing cellulose by the action of cellulase (enzyme).

The following techniques have been proposed in order to create an environment in which cellulase works as easily as possible in this hydrolysis reaction. (1) Japanese Examined Patent Publication No. 57-58001; cellulose as a raw material is treated in a mixed solution of concentrated hydrochloric acid and concentrated sulfuric acid to process the cellulose into cellulose that is easily decomposed into cellulase. (2) JP-A 1-256394; An ultrafiltration reactor is provided in the reaction system to remove reaction inhibitors in the ultrafiltration reactor.

[0004]

However, in these techniques, (1) cellulose must be processed, and (2) reaction inhibitors are removed, so that the hydrolysis reaction by cellulase is inhibited. However, it is difficult to mass-produce cellooligosaccharides at low cost because cellooligosaccharides cannot be selectively obtained. As a result, cellooligosaccharides are very expensive.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for producing cellooligosaccharides, which allows cellooligosaccharides to be obtained inexpensively and conveniently.

[0006]

MEANS FOR SOLVING THE PROBLEMS The present inventors have found that (1) crystalline cellulose has a strong hydrogen bonding force between glucose units constituting the crystalline cellulose. Therefore, the hydrolysis rate of this crystalline cellulose by cellulase is high. Is slow. Also,
In this hydrolysis, a glucose-rich hydrolyzate (product) is obtained by the action of β-glucosidase contained in cellulase. (2) Amorphous cellulose is easily hydrolyzed by cellulase, and this hydrolysis Although cellooligosaccharide and glucose are obtained by this method, more glucose is obtained than cellooligosaccharide by the action of β-glucosidase contained in cellulase in this hydrolysis. (3) β-glucosidase is adsorbed by lignin Based on the phenomenon that (4) cellobiose produced by the hydrolysis reaction has an inhibitory effect on cellulase decomposition, cellulase is caused to act on a cellulose raw material containing a large amount of amorphous cellulose, and Β-glucosidase in cellulase to lignin It was found that cello-oligosaccharides can be selectively obtained by adsorbing them to inhibit the action of β-glucosidase and collecting at least cellobiose from the reaction solution at any time among the cellooligosaccharides produced by this hydrolysis reaction. .

Therefore, in the method for producing cellooligosaccharides of the present invention, a hydrolysis reaction in which a cellulosic material containing a large amount of amorphous cellulose is hydrolyzed by the action of cellulase to produce cellooligosaccharides is carried out in the presence of lignin. At the same time, at least cellobiose among the cellooligosaccharides produced by this hydrolysis reaction is optionally collected from the reaction solution.

[0008]

According to the method for producing cellooligosaccharides of the present invention, the cellulose raw material containing a large amount of non-crystalline cellulose is hydrolyzed by the action of cellulase to produce cellooligosaccharides. At this time, β-glucosidase, which produces glucose from cellooligosaccharide in cellulase, is inactivated by being adsorbed by lignin, so that the action of the endo-type enzyme in cellulase on the cellulose raw material becomes dominant. Further, the cellobiose thus produced is collected from the reaction solution, thereby inhibiting the cellulase decomposition reaction from being inhibited. As a result, cellooligosaccharides are selectively produced. In this reaction system, as the cellulose raw material contains a larger amount of non-crystalline cellulose, the hydrolysis reaction proceeds more easily and cellobiose is selectively obtained.

[0009]

EXAMPLE A specific example of the present invention will be described below.

In the method for producing cellooligosaccharides according to one embodiment of the present invention, first, for example, unbleached pulp (containing amorphous cellulose and lignin) obtained as a product during the pulp production process is used as a raw material. 2 wt% of bleached pulp
Create a slurry liquid. The pH of the slurry liquid was adjusted to 5.5 by adding acetic acid to the slurry liquid while stirring the slurry liquid, and then the slurry liquid was adjusted to 45
Warm to ℃. While maintaining this temperature, 0.1 wt% of cellulase (Trichoderma viride
(Origin) is added and stirred for 20 minutes to cause cellulase to act on the cellulose to hydrolyze the cellulose.

When this hydrolysis reaction solution was filtered through, for example, an ultrafiltration membrane, a sugar solution in which cellobiose accounted for 80% or more was collected.

Next, as a comparative example, KC Flock W-50
(Cellulose raw material; manufactured by Sanyo Kokusaku Pulp Co., Ltd.) was used as a raw material to carry out the same hydrolysis reaction as in the above-mentioned Examples. When the reaction solution in this comparative example was filtered through the ultrafiltration membrane, a sugar solution having a cellobiose content of 20% or less was collected. The hydrolysis reaction was continued for a further 1.5 hours, and the reaction solution was filtered through an ultrafiltration membrane in the same manner. As a result, a sugar solution containing mostly glucose was collected.

[0013]

EFFECTS OF THE INVENTION According to the present invention constituted as described above, cellobiose is optionally included in the cellooligosaccharides produced by the hydrolysis reaction by adsorbing β-glucosidase in cellulase to lignin to inactivate it. Cellooligosaccharides can be obtained inexpensively and easily by collecting from the reaction solution.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuo Koshishima 4-6-23 Kashima, Yodogawa-ku, Osaka City, Japan Chemical Machinery Manufacturing Co., Ltd. (72) Inventor Takahiko Tsunomiya 4-chome, Kashima, Yodogawa-ku, Osaka No. 23 In Japan Chemical Machinery Manufacturing Co., Ltd. (72) Inventor Masami Sasaya 4-6-23 Kashima, Yodogawa-ku, Osaka City Japan Chemical Machinery Manufacturing Co., Ltd.

Claims (1)

[Claims] 1. A cellulosic material containing a large amount of non-crystalline cellulose is hydrolyzed by the action of cellulase to produce a cellooligosaccharide in the presence of lignin, and is produced by this hydrolysis reaction. A method for producing cellooligosaccharides, characterized in that at least cellobiose of the cellooligosaccharides is optionally collected from the reaction solution.