JPS60164494A - Method for pretreatment of enzymic hydrolysis of cellulosic wood - Google Patents

Abstract

PURPOSE:To improve the enzymic hydrolysis ratio of coniferous wood, e.g. pine or SUGI, by irradiating the coniferous wood with electron rays or gamma-rays, blasting the wood, and if necessary pulverizing the blasted wood. CONSTITUTION:Cellulosic wood is irradiated with electron rays or gamma-rays at >=10<6> rad and <=10<8> rad, blasted and if necessary further pulverized. Coniferous wood such as pine or SUGI is finely powdered in a short time by pulverization to remove lignin from the surface of cellulose. Thus, the surface area of the cellulose is increased to improve remarkably the enzymic hydrolysis rate and hydrolysis ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pretreatment method for enzymatic hydrolysis of cellulosic materials.

In recent years, widespread attempts have been made to decompose cellulose, which is abundant in nature, to produce glucose, which is a resource for energy, food, and industrial raw materials.

As a method for decomposing cellulose into glucose, enzymatic hydrolysis is being used because the reaction proceeds under mild pressure and temperature conditions, is specific, and does not cause secondary decomposition.

However, natural cellulose found in wood, rice straw, wheat straw, corn stalks, leaves, bagasse, and paper is generally highly crystalline and is mixed with lignin, ash, etc., so it cannot be degraded by enzymatic hydrolysis. It has the drawbacks of strong resistance to oxidation, slow reaction rate, and low decomposition rate.

In order to eliminate this drawback, prior to enzymatic hydrolysis, explosion crushing, mechanical crushing using a ball mill, etc., high-temperature heating crushing, r
Cellulose with enhanced amorphous properties such as destruction by radiation irradiation,
Physical pretreatments that increase the reaction surface area, reagents such as phosphoric acid, sulfuric acid-monochlorinated zinc chloride, cadoxene, and sodium hydroxide that disrupt the crystalline structure of cellulose, and chemical methods such as dissolving and removing lignin can be used. This is done as a pre-treatment.

The above pretreatment method is effective for herbs such as rice straw, wheat straw, bagasse, and hardwoods such as beech and oak. If this is done, enzymatic hydrolysis of t'z of the cellulose contained can be 100%'.

However, softwood materials such as cedar and pine are more resistant to enzymatic hydrolysis than herbaceous and hardwood materials due to differences in physical structure, degree of polymerization of lignin species and cellulose, and degree of crystallinity. Therefore, it is difficult to improve the decomposition rate even with simple physical or chemical pretreatment.

This invention was obtained as a result of studies on a pretreatment method for increasing the enzymatic hydrolysis rate of softwood materials such as cedar and pine from the above-mentioned viewpoint.

That is, the present invention involves irradiating softwood materials such as cedar and pine with electron beams or r-rays at IO'rad or more and 10'rad or less, and then blasting the material, and if necessary, further crushing the material beforehand. This is a treatment method that has succeeded in increasing the enzymatic hydrolysis rate of coniferous materials such as cedar and pine. After treating cellulose materials with high-temperature, high-pressure steam, they are released all at once under atmospheric pressure. Explosive pretreatment is also an effective enzymatic hydrolysis pretreatment method for herbs and hardwoods.

By treating natural cellulosic materials containing lignin with saturated steam and then exploding them under atmospheric pressure, the molecular weight of cellulose is reduced, lignin is released from the fibers, and the fibers become single fibers, and the fiber length is also shortened. .

The removal of lignin from the cellulose surface and the cutting of the cellulose fibers into shorter lengths increases the surface area of cellulose and increases the rate and degradation rate of enzymatic hydrolysis; The cleavage of β-1,4-glucoside bonds in cellulose, which is an elementary reaction, occurs due to explosion and promotes enzymatic hydrolysis.Herbs and hardwoods are exposed to a pressure of 20 to 28 atm, approx. 10~z
6υN, , c/J spores and mature air (↓lυ) The above effects were shown by explosion under atmospheric pressure, and the rate of enzymatic hydrolysis and decomposition rate increased. be enhanced.

However, about 210~280℃ for softwood materials, 20~
When treated with saturated steam at 28 atmospheres for less than 10 minutes and then exploded under atmospheric pressure, it was difficult to form single fibers, and the fibers remained long, indicating that the lignin that firmly attached to the cellulose part was difficult to release. Since lignin is piled up on the cellulose surface, enzymatic hydrolysis is difficult to proceed.

Treatment with saturated steam for a long time can increase the effect and increase the rate and decomposition rate of enzymatic hydrolysis, but this requires treatment with saturated steam for a fairly long time. .

The present inventors previously applied electron beams or γ-rays to I O' ra
By irradiating cellulosic materials under conditions of d or more and 108 rad or less, lignin is easily released from the cellulose surface even when it is exploded after being treated with saturated steam for a short time, resulting in monofilament [7]. They discovered that the rate of enzymatic hydrolysis and decomposition rate can be increased.

The amount of Klason lignin in cellulosic material is 10'ra
It has been reported that Klason lignin wrinkles are slightly reduced by irradiation with electron beams or gamma rays of d or higher. The present invention utilizes this improvement in the reactivity of lignin by irradiation with electron beams or r-rays.

However, in the case of coniferous trees, cellulose and lignin are finely bonded, so even if the cellulose is irradiated with electron beams or r-rays and then exploded, there are many areas where the cellulose surface is covered with lignin, and sufficient enzymatic hydrolysis is not possible. Obtaining a high rate is a hot topic.

Irradiation treatment with rays or gamma rays as a pretreatment for highly crystalline cellulosic materials containing lignin can (1) reduce the degree of polymerization of cellulose (2) reduce the amount of crystals (formation of reducing sugars). 4) It is known that there is a mechanical deterioration effect.

The effects of (1), (2), and (a) above become particularly noticeable when the irradiation dose is IO"rA'd or more, but the effect of (4) is This is obvious even with an irradiation dose of about IO'rad.

This effect is exhibited even after irradiation with electron beams or gamma rays and further blasting; the coniferous wood becomes finely pulverized in a short time by crushing, lignin is removed from the cellulose surface, the cellulose surface area increases, and enzymatic hydration It is possible to dramatically increase the decomposition speed and decomposition rate.

Examples of the present invention will be described below along with comparative examples.〇Comparative Example 1 10aX lO+gX 125gm of cedar horn (triple base weight) is used as a cellulose material, and 300g of it is placed in a reaction tank of a batch type blasting treatment device (2/tani). After replacing the inside of the reaction tank with water vapor for 20 seconds, the temperature was reduced to 27 atm (approximately 220°C).
The pulp was treated with saturated steam for 4 minutes, 8 minutes, and 16 minutes, respectively, and then the ball pulp was opened and exploded under atmospheric pressure.

The obtained sample had a fiber length of 125III after 4 minutes of treatment.
I! 1 These samples were filtered through a 400-mesh wire mesh to remove condensed water, and the dry weight was Ig.
Pour into a Mayer flask, add 0.1 molar acetic acid M solution with pH 4.9 to make it 50 m/ml, and then add cellulose hydrolase (sieve product name: Cellulase Onozuka R-10).
, Kinki Yakult Co., Ltd.) was added to perform enzymatic hydrolysis in a reciprocating culture incubator at 45°C, and the amount of glucose produced in the reaction solution was measured after 168 hours. A voice that emphasizes the decomposition rate.

Each minute i! *The rates are shown in Table 1. The glucose elevation in the reaction solution was measured using a glucose measuring device (Yellow Springay/Strument, YSI) using an immobilized enzyme membrane.
mode/23A).

Example 1 The same cellulosic material used in Comparative Example 1 was coated with 24
Explosion was carried out in the same manner as in Comparative Example 1, except that electron beam irradiation was performed at 10 rad and 48 X 10 rad, and then treatment with saturated steam was performed for 2 and 4 minutes.

The sample length of the obtained samples was 20 to 40 mm when irradiated with 24 x 10' rad and treated with saturated steam for 2 minutes, 2 to 1 Om when treated with saturated steam for 4 minutes, and 5 mm when irradiated with 48 x 10' rad and treated with saturated steam for 2 minutes. -10 mm, 1-5 m after 4 minutes of saturated steam treatment.

Condensed water was removed from these samples in the same manner as in Comparative Example 1,
Enzymatic hydrolysis was performed and the amount of glucose in the reaction solution was measured. The enzymatic hydrolysis rate t calculated from the amount of glucose produced after 168 hours is shown in Table 1.

Table 1 Comparative Example 2 Each sample obtained in Comparative Example 1 was ground in a 100 ml cutter mill for 3 minutes, then ground in a 200 m/vol ball mill for 3 hours, and subjected to enzymatic hydrolysis in the same manner as in Comparative Example 1. The enzymatic hydrolysis rate was calculated from the measurement of the amount of glucose produced in the reaction solution after 168 hours, and is shown in Table 2.

Example 2 Each sample obtained in Example 1 was ground for 3 minutes using a 1100 m/volume cutter mill, then ground for 1 to 3 hours using a 200 m/volume ball mill, and enzymatic hydrolysis was performed in the same manner as in Comparative Example 1. . The enzyme hydrolysis amount N5 was calculated from the measurement of the amount of glucose produced in the reaction solution after 168 hours, and is shown in Table 2.

From the above table in Table 2, it is demonstrated that if the pretreatment method of the present invention is adopted, a high enzymatic hydrolysis rate can be obtained, and the effect of electron beam irradiation greatly contributes to shortening the blasting treatment time and the crushing time. It was done.

Patent applicant: New Fuel Oil Development Technology Research Association Representative: Patent Attorney Kazu1) Akira

Claims (1)

[Claims] (1) The cellulosic material has an IO'rad or more of 10” rad.
1. A pretreatment method for enzymatic hydrolysis of cellulosic material, characterized in that a cellulose material is subjected to an electron beam or gamma ray irradiation treatment in advance at a temperature of d or less, and then subjected to an explosion treatment. Q) The pretreatment method for enzymatic hydrolysis of cellulosic material according to claim 1, characterized in that the cellulosic material subjected to electron beam or gamma ray irradiation treatment and subsequent blasting treatment is further pulverized. (3) The pretreatment method for enzymatic hydrolysis of cellulosic material according to claim 1 or 2, wherein the cellulosic material is a softwood material such as cedar or pine.