JPS6087799A - Cutting and crushing pretreatment of cellulosic material for enzymatic saccharification - Google Patents

Abstract

PURPOSE:To improve the enzymatic saccharification ratio of a cellulosic material, by cutting and crushing a cellulosic material mechanically with a rotary cutter, and carrying out the enzymatic saccharification. CONSTITUTION:A cellulosic material is conditioned to a water-content of preferably <=40wt%, especially about 10wt% corresponding to the air-dried state, and cut mechanically at room temperature with a rotary cutter having a rotary rod furnished with plural edges at the circumference. The cut cellulosic material is subjected to the conventional enzymatic saccharification process.

Description

Detailed Description of the Invention Regarding the pretreatment method by cutting and crushing, more specifically, when cellulosic materials such as pulp, cellulose in papermaking sludge, and waste paper are decomposed and saccharified using cellulose-degrading enzymes, the cellulose is The present invention relates to a pretreatment method in which a cellulosic substance is mechanically cut and crushed in order to improve the enzymatic decomposition rate of the cellulosic substance.

Conventionally, methods for enzymatically decomposing and saccharifying cellulosic materials such as wood have been researched in various fields, and in particular, in methods for saccharifying cellulosic materials that utilize enzymes containing cellulase, which is a cellulolytic enzyme, the cellulosic materials are It is said that it is necessary to destroy the structure of the substance. This is because in the cellulosic substance, cellulose has a linear crystal structure in which glucose is linked with β-1.4,
Moreover, due to the coexistence of lignin, which is difficult to enzymatically decompose, enzymatic decomposition efficiency is low if it is left alone. Therefore, in order to improve this enzymatic decomposition efficiency, it is necessary to destroy the crystal structure of cellulose in advance or perform delignification. This is because it is necessary.

Conventionally, methods for destroying the crystal structure of cellulose include, for example, pulverizing the cellulose to a particle size of 50 μm or less using a ball mill, freezing and pulverizing, and radiation irradiation.

However, these methods require a long time to destroy the cellulose structure.

For this purpose, a large amount of electrical energy is required, especially in the freeze-grinding method and the radiation irradiation method, in addition to a large amount of electricity, special processing equipment is required. It has drawbacks such as the need for special equipment with a temperature range of -4 to -100°C.

On the other hand, various treatment methods related to delignification (1) include ozone treatment, alkali treatment using sodium hydroxide, sodium carbonate, etc., and oxygen/alkali treatment.

The present inventors have overcome the drawbacks of conventional methods for destroying the crystal structure of cellulose, and have made it possible to easily destroy the crystal structure of cellulose in a cellulose material in a short time as a pretreatment for enzymatic saccharification of the cellulose material. As a result of intensive research to provide a method for mechanical destruction, it was discovered that the purpose could be achieved by using a rotary cutter, that is, a rotating rod with multiple blades around the circumference, and this knowledge was achieved. Based on this, the present invention was completed.

That is, the present invention provides a method for cutting a cellulosic material, which is characterized in that, prior to enzymatic saccharification of the cellulosic material, the cellulosic material is mechanically cut and crushed by rotating a rod having a plurality of blades. This provides a pretreatment method using a pulverization method.

The cellulosic material used in the present invention is not particularly limited as long as it contains cellulose, but cellulosic materials such as pulp, cellulose in papermaking sludge, and waste paper are suitable.

Next, an example of a cutting and crushing device used in the present invention is shown in FIG. In FIG. 1, A and B are perspective views of the lid and main body of the crushing container, respectively, C and D are a sectional view and a perspective view of the rotary cutter, respectively, and the reference numeral 1 is the container main body;
2 is the lid of the container, 3 is the main body of the rotary cutter, and 4 is its blade.

To carry out the present invention, first, a cellulosic material of an appropriate size and a rotary cutter are placed in a container of a cutting and grinding device, and the cutter is rotated at room temperature to cut and grind the cellulosic material.

In this cutting and crushing, the moisture content of the cellulosic material is preferably 40% by weight or less, especially 1%, which corresponds to an air-dried state.
Those with a weight of around 0 weight are preferable because they have the highest saccharification rate in the subsequent decomposition and saccharification.

Regarding the cutting and crushing time, the longer the time, the higher the saccharification rate, but about 5 minutes is sufficient. example td
In the decomposition and saccharification of thermomechanical pulp using cellulase, the saccharification rate is approximately 9% when pretreatment of cutting and crushing is not performed, whereas when pretreatment of cutting and crushing is performed for 5 minutes, the saccharification rate is approximately 33%. improve.

In the conventional ball milling method, fibers are pulverized by grinding, whereas in the cutting and pulverizing method of the present invention, the fibers are cut mainly perpendicularly to the axial direction of the fibers, resulting in a large amount of cellulose in a short time. The crystal structure of is destroyed.

Therefore, the cutting and pulverizing method of the present invention greatly improves the saccharification rate compared to the conventional ball milling method.

The cellulosic material thus cut and ground can be used as is or, if necessary, after a delignification treatment, using commonly known saccharifying enzymes, such as Aspergillus sp., Irpex fi, etc.)! j It is cyolyzed and converted into sugars by cellulase-containing enzymes produced by various microorganisms such as Coderma.

The pretreatment method using the cutting and pulverizing method of the present invention is compared to the conventional pretreatment method that destroys the crystal structure of cellulose.
The operation is extremely simple and can be carried out in a single hour, and the cellulosic material cut and ground by this pretreatment method provides saccharides with a high saccharification rate to cellulase-containing enzymes.

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

Example 1 As a cutting and crushing device, an inner diameter of 60 m as shown in Fig. 1 was used.
m, a stainless steel cylindrical container with a height of 90πm and 18
A device having a stainless steel rotary cutter with a diameter of 45 tttm and a length of 56 mm and having two blades was used, and commercially available thermomechanical pulp (softwood: M wood) was used as the cellulosic material.

The pulp was pulverized by a cutting pulverization method, and the relationship between pulverization conditions and saccharification rate was investigated. In addition, 2.51 (absolute dry weight) of thermomechanical pulp was pulverized as the amount of pulverization shown in FIG.

In addition, the saccharification rate was determined as follows.

That is, the air-dried pulverized sample 0.2.j9 obtained by the above-mentioned cutting and pulverization method was added with a 0.1 molar acetate buffer (pH 5,
0) 10ttti was added and incubated at 40°C. After 48 hours, the decomposition liquid was filtered through a 304 glass filter, and the undecomposed residue was dried at 105°C and its weight was measured. In addition, the amount of glucose in the obtained filtrate was determined, and the value obtained by multiplying this amount of glucose by 0.9 was defined as anhydrous sugar.
This was divided by the substrate to obtain the saccharification rate.

The relationship between the grinding conditions and the saccharification rate is shown in FIGS. 2 and 6.

Figure 2 shows the relationship between the moisture content and saccharification rate of the thermomechanical pulp used for cutting and crushing under the conditions of a crushing time of 5 minutes and a crushing temperature of room temperature, and Figure 3 shows the relationship between the moisture content and saccharification rate of the thermomechanical pulp at a crushing time of 5 minutes and a crushing temperature of room temperature.
This figure shows the relationship between the grinding time and the saccharification rate when thermomechanical pulp is cut and ground at room temperature.

As can be seen from Figure 2, the water content in the sample at the time of crushing is 0~
Those with a moisture content of 40% have a high saccharification rate, and in particular, those with a moisture content of around 10% (air-dried) have the highest saccharification rate.

Moreover, as can be seen from FIG. 6, the saccharification rate significantly improved as the grinding time increased, and 32% of the substrate was saccharified after 5 minutes of grinding.

That is, it can be seen that the cutting and pulverizing method of the present invention has an excellent effect of destroying the cellulose crystal structure.

Example 2 The same thermomechanical pulp used in Example 1 was used as the cellulosic material, and the pulp was pulverized by a cutting and pulverizing method using an apparatus as shown in FIG. 1 and a conventional ball milling method. .

The particle size distribution of the pulp after crushing was compared, and the saccharification rate by cellulase was also investigated.

The cutting and crushing conditions were as follows: Pulp sample Lk2-5.9 (absolute dry weight), pulp moisture content 7.1 weight 1L crushing time was 5 minutes, and ball mill crushing conditions were as follows: Pulp sample amount Lk2-5.9 (absolute dry weight)
Pulverization was carried out at 0g (absolute dry weight), pulp moisture content of 9.2% by weight, and pulverization time of 1 hour.

The results are shown in Table 1.

As can be seen from this table, when comparing the saccharification rates between the cutting and pulverizing methods and the ball milling method, the cutting and pulverizing method is superior.

This is due to the difference in the pulverization mechanism; in the cutting and pulverizing method, the fibers are mainly cut in a direction perpendicular to the fiber axis direction, whereas in the ball milling method, the fibers are pulverized by attrition. Therefore, the cutting and pulverizing method destroys more of the crystalline structure of cellulose in a shorter time than the ball milling method, so that the saccharification rate is further improved.

Example 3 As the cellulosic material, simple precipitated sludge and coagulated precipitated sludge from a wastewater treatment process of a pulp mill containing about 20 to 60% by weight of pulp fiber based on solid content were used. In addition, for simple sedimentation sludge, the solid content concentration is approximately 2
By freeze-drying sludge with a weight of about Hk%,! l
ll prepared. Furthermore, the flocculated and precipitated sludge was once defibrated with water and then freeze-dried in the same manner as the simple precipitated sludge.

The above-prepared sample was pulverized for a minute using the cutting pulverization method to examine the saccharification efficiency. The saccharification rate was measured in the same manner as in Example 1. The results are shown in Table 2.

Table 2 From this table, the saccharification rate of the pulverized sample is improved by about 20 to 90 times compared to the unpulverized sample, indicating that the cutting and pulverization method is superior as a pretreatment method for the decomposition and saccharification of cellulosic substances using cellulase. I understand.

[Brief explanation of the drawing]

Figure 1 shows one example of the cutting and crushing device used in the present invention, where A and B are perspective views of the lid and main body of a crushing container, respectively, and C and D are a cross-sectional view and a perspective view of a rotary cutter, respectively. be. 2 and 3 show the relationship between the crushing conditions and the saccharification rate of the thermomechanical pulp in Example 1, and FIG. 2 is a graph showing the relationship between the moisture content of the pulp and the saccharification rate. , FIG. 3 is a graph showing the relationship between grinding time and saccharification rate. Patent applicant Kawa, Director of the Agency of Industrial Science and Technology 1) Yube designated agent
Sei Mima, director of the Shikoku Industrial Technology Testing Institute, Agency of Industrial Science and Technology - Figure 1 (8) Figure 2: Kagagi Mu (phantom Figure 3 #R Takeji Takema)

Claims (1)

[Scope of Claims] 1. A pretreatment method for a cellulosic material by cutting and pulverizing the cellulosic material, which comprises mechanically cutting and pulverizing the cellulosic material using a rotary cutter before enzymatically saccharifying the cellulosic material. 2 The cellulosic material has a moisture content of 40% by weight or less,
The pretreatment method according to claim 1, wherein the cutting and pulverizing are carried out at room temperature.