JPS5858076B2 - Cellulose saccharification method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for enzymatic saccharification of cellulose, and more specifically to a method for saccharification of wood, in which crushed cellulose is treated with ozone and then enzymatically decomposed.

In the past, methods for enzymatically decomposing and saccharifying cellulose-containing materials such as wood have been studied in various fields, and in particular, wood saccharification methods that utilize cellulase-containing enzymes are said to require destroying the wood tissue. ing.

Examples of methods for destroying the structure of such cellulose-containing material fl include a method of pulverizing it to a particle size of 50 μm or less using a ball mill, a freeze-pulverization method, a radiation irradiation method, and the like.

However, these methods take a long time to destroy the structure of cellulose, usually 15 to 16 hours, and require a large amount of electrical energy, especially the freeze-grinding method and the radiation irradiation method, which require a large amount of electrical energy. It is necessary to create special processing equipment and operating environments.

On the other hand, the chlorite method and peracetic acid method are known as chemical tissue destruction methods, but they not only require large amounts of these chemicals, but also require large amounts of chemicals and lignin-containing treatments. There is a drawback that a large amount of expense is required for processing the waste liquid for disposal.

The present inventors have overcame the deficiencies of conventional methods for chemically destroying the tissue of cellulose-containing substances, and have conducted repeated research on a method for effectively chemically destroying the tissue and saccharifying cellulose through enzymatic decomposition. As a result, we found an extremely effective method.

In the present invention, a cellulose-containing material that has been ground into fibrous or granular form is treated with ozone under conditions of a moisture content of 30 to 90% by weight to destroy its structure, and then enzymatically decomposed by allowing enzymes including cellulase to act on it. The gist of this paper is a method for saccharification of cellulose, which is characterized by the following.

For example, wood, which is a typical cellulose-containing material, is composed of three components: cellulose, hemicellulose, and lignin.The proportions vary depending on the tree species, but usually cellulose is 40 to 50% by weight, hemicellulose is 20 to 30% by weight, and lignin. It consists of about 20 to 30 weight coefficients.

As described above, the wood tissue of such constituent components is destroyed as much as possible by various means, and then saccharified by cellulase-containing enzymes.

In the present invention, the cellulose-containing material is ground into fibers or granules.

In this case, for example, the wood can be easily ground into fibers or granules using a conventional mechanical piping method such as a Uille-type grinder or a disc refiner.

The tissue of the thus obtained pulverized product is destroyed by the action of ozone in the presence of water, and is effectively decomposed and saccharified by saccharifying enzymes.

However, if the diameter of the pulverized product is 5 mm or more, it is inconvenient because little improvement in the enzymatic decomposition rate of the ozonated product can be expected.

Accordingly, in the present invention, it is desirable that the cellulose-containing material be pulverized into fibers or particles smaller than 5 mm.

The ground cellulose-containing material is then treated with ozonation in the presence of water to chemically disrupt its structure.

In this ozone treatment, it has been found that the amount of admixture water, mainly adhering water and impregnating water, present in the cellulose-containing substance and in contact with the cellulose-containing substance has a very large effect on the enzymatic decomposition rate.

The amount of ozone used to treat the cellulose-containing material varies depending on the pulverization state of the cellulose-containing material and the amount of water present, but the amount of ozone used to treat the cellulose-containing material varies from
The degree preferably 10 to 25 weight φ is conveniently adopted,
A suitable amount is selected depending on other conditions.

In the present invention, ozone is preferably applied in gaseous form to the pulverized hydrated cellulose.

In addition, ozone only needs to destroy the structure of the cellulose-containing material, and a sufficient amount for that purpose is advantageously used. During the destruction treatment, the crushed cellulose-containing material should be adjusted to have a moisture content of 30 to 90 weight φ. This is very important.

When the water content deviates from the above range, the decomposition rate of the ozone-treated cellulose by enzymes decreases, which is not preferable.

This will be further clarified in the specific examples below.

Such a moisture content can be easily adjusted by immersing the crushed cellulose-containing material in water and then squeezing it, for example.

The ozonated cellulose-containing material is decomposed by commonly known saccharifying enzymes, such as cellulase-containing enzymes produced by various microorganisms such as Aspergillus, Irpex, and Trichoderma.

In this way, cellulose-containing substances are saccharified and converted into monosaccharides.

Compared to conventional methods for saccharification of cellulose-containing substances, the method of the present invention is extremely simple to operate, has no concerns about environmental pollution such as water pollution, and can obtain reducing sugars at a high saccharification rate. can.

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

Example (1) Thermomechanical pulp (hereinafter referred to as TMP) was obtained by treating red pine pulp with a pressurized disc refiner.

This undried TMP (moisture content: 69.6%) 16.4Fl (
5 g of dry TMP) was collected in a 500 ml eggplant-shaped flask, and while it was attached to a rotary evaporator and rotated, 3 volumes of ozone was added to 200 m of ozone from one end.
Aeration was performed at a flow rate of μ/pongee, and the tissue was destroyed by discharging from the other end.

Various treated samples were prepared with different aeration times, in other words, with different amounts of ozone action, and they were washed with water and air-dried.

To each 2 g of the ozonated air-dried sample obtained in this way,
0 containing commercially available cellulase (meicelase) 50
, add 10-1 molar acetate buffer (pH 5,0),
Incubate at a temperature of °C.

After 48 hours, the decomposed solution was filtered through a 3G glass filter once, and the undecomposed residue was thoroughly dried at a temperature of 105°C and its weight was measured.

In addition, the reducing sugar content of the obtained liquid f was determined, and the relationship between the amount of ozone action and the pulp decomposition rate is summarized in Table 1 below.

For comparison, an experiment was conducted on TMP without ozone treatment under the same enzymatic decomposition conditions as above, and the results are also listed in the table below.

As can be seen from the table above, the reducing sugar production rate of TMP untreated with ozone is 1.9%, while that of TMP treated with 1 weight width ozone is 5.0%, and as the amount of ozone action increases, The reducing sugar production rate, that is, the saccharification and decomposition efficiency increases.

However, TMP with a water content of 69.6φ showed the maximum decomposition rate by enzymes when 24 weight of ozone was applied.
At an ozone action amount of 36% by weight, there is a tendency for the decomposition rate to decrease somewhat.

Actual Example 2 The TMP obtained in Actual Example 1 was air-dried, and 5 g of it was collected as a completely dry net weight. After immersing it in water for 1 hour, deaeration treatment was performed for 50 minutes, and the sample was thoroughly soaked with water. Samples with various moisture contents were prepared by dehydration on a Buchner funnel.

6φ of ozone was passed through each of these, and the post-treatment was then carried out in the same manner as in Example 1.

The sample thus obtained was subjected to enzymatic decomposition and treated in the same manner to determine the relationship between the water content and saccharide degradation rate of the sample.

The results are shown in Table 2. It can be seen that when approximately 6 parts by weight of ozone is applied to TMP of Japanese red pine, the enzymatic decomposition rate peaks when the water content is around 46 parts by weight.

Example 3 Red pine wood flour (60-80 mesh, extracted with alcohol and benzene) and the air-dried TMP of Example 2 were adjusted to have a moisture content of 50-54 by weight using the method shown in Example 2, and were exposed to ozone for various times. After aeration, the relationship between the amount of ozone action and the saccharide decomposition rate was determined in the same manner as in Example 1.

Claims (1)

[Claims] 1. A cellulose-containing material ground into fibrous or granular form,
A method for saccharification of cellulose, which comprises treating the cellulose with ozone under a moisture content of 30 to 90 weight to destroy its tissue, and then enzymatically decomposing the cellulose by applying an enzyme containing cellulase. 2. The method according to claim 1, wherein the cellulose-containing material is wood. 3. Claim 1, in which ozone is applied in multiple amounts of ■ to 30% by weight with respect to the dry absolute amount of the pulverized cellulose-containing material.
2. The method according to any one of paragraphs 1 and 2. 4. The method according to any one of claims 1 to 3, wherein the cellulose-containing material is pulverized into fibrous or granular particles of 5 mm or less.