JPS5839520B2 - Method for saccharification of cellulose substances - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for saccharifying cellulose materials such as paper, wood chips, sawdust, straw, rice husks, etc. into monosaccharides such as glucose.

Although there is a huge amount of unused cellulosic material of this kind,
Currently, it is hardly used (it is incinerated).

Recently, due to the strong desire to develop alternative energy to petroleum, it has become possible to saccharify unused cellulose materials and reuse them as an energy resource.

In other words, monosaccharides are obtained from cellulose materials, which are then converted into ethanol through alcoholic fermentation, fermentation technology, etc.
Converted into other chemicals using chemical technology.

The technical and economic problem here is cellulose saccharification technology.

Methods for saccharification of cellulose include chemical methods in which hydrolysis is performed using sulfuric acid, hydrochloric acid, etc., and biological methods in which decomposition is performed using enzymes or microorganisms.

Although the former has been studied for a long time, it is economically difficult to put it into practical use.

On the other hand, since the latter is a biochemical reaction, it is carried out under mild reaction conditions, and therefore it is seen as promising because it requires less energy and less chemicals.

Cellulose is decomposed into glucose by the enzyme cellulase, but it is difficult to directly apply the aforementioned unused cellulose material to this biochemical decomposition reaction, and it is necessary to pre-treat it in advance to make it easier to decompose. be.

Pretreatment methods include steaming with caustic soda, mechanical crushing, and radiation irradiation, but none of these techniques has yet been established.

The present invention was made in view of the above-mentioned circumstances and provides a method for effectively pretreating cellulose materials with simple operations.

That is, the present invention provides a method for treating a cellulose material, which is characterized by carrying out an oxidation treatment using air, oxygen, or ozone in the presence of an alkali as a pretreatment when the cellulose material is biochemically decomposed and saccharified. This is a saccharification method.

Hereinafter, this invention will be specifically explained with reference to the drawings.

When the target cellulose material retains its natural form, such as wood chips or straw, it is first defibrated in a defibration step 1.

That is, a cellulose material is supplied to the same process 1 through a supply pipe 2, and caustic powder and steam are introduced through conduits 3 and 4, respectively, for steaming, and fibrillation is performed using a fibrillator such as a refiner.

Caustic soda has a concentration of 9~ as Na2O for cellulosic materials.
It will be 11%.

This delignifies and defibrates the cellulosic material to a certain extent, refining the cellulosic material from its natural form.

Note that this defibration may be performed by a general bulking method, but in this case, a large amount of chemicals is required, and the amount of waste liquid is also increased, which has the drawback of increasing the size of the processing equipment.

Furthermore, if the target cellulosic material is already powdered or deligris-treated, such as the screw part of waste paper bagasse, the defibration step may be omitted.

Next, the defibrated cellulose is sent to the pretreatment tank 5, and alkali and air are introduced into the cellulose through conduits 6 and 7, respectively.

Caustic soda is commonly used as the alkali, but the alkali is not limited thereto.

Oxygen or ozone may be used instead of air.

Also, heating steam is introduced from the conduit 8.

When the oxidation treatment is performed in the presence of an alkali, delignification and swelling of the defibrated cellulose occur, and a saccharification raw material is obtained.

Furthermore, iron ions and cobalt ions may be added as oxidation promoters.

After washing the saccharified raw material pretreated in this way, it is sent to a saccharification process 9, and a cellulase-containing liquid is introduced into the same process from a conduit 10 to saccharify cellulose.

After saccharification, the sugar-containing liquid is sent to the fermenter 11, and the same is passed through the conduit 12.
yeast is introduced to convert sugar into alcohol.

The resulting alcohol is sent to a conventional distillation process. Example a Defibrated Ematsu chips were used as the cellulose material, divided into two parts, and each sample was defibrated using a disk refiner under the following two conditions.

b. Pretreatment Each defibrated cellulose material was pretreated under the following two conditions.

The cellulose material thus oxidized in the presence of an alkali was subjected to a ball mill treatment, and the P aqueous property (freeness) was measured.

For comparison, the P water content of kraft pulp was also measured in the same manner as above.

The results are shown in Figure 2. As can be seen from the figure, the pretreated cellulosic material requires about half the processing time compared to kraft pulp to reach the required r-aqueous properties.

This indicates that the fiber structure has become porous due to swelling.

That is, cellulose is in a form that is susceptible to saccharification by the following enzymes.

Regarding delignification, a comparison was made between cases where oxidation treatment was performed and cases where no oxidation treatment was performed in the pretreatment.

As a result, the lignin content in the former was about 6 to 8%, while in the latter, even if the amount of caustic soda added was increased to 7.3%, about 17% of lignin remained.

Therefore, it can be seen that delignification significantly progressed due to the oxidation treatment.

Since the present invention is configured as described above, cellulose materials can be pretreated to a state where they are easily decomposed and saccharified by relatively simple operations, and therefore the saccharification reaction can be carried out quickly.

In addition, since the oxidation treatment is performed using air, oxygen, or ozone, the amount of alkali used can be reduced, making it easy to perform processes such as washing with water to remove alkali, which is also excellent in terms of pollution prevention. .

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention, and FIG. 2 is a graph showing the relationship between ball mill processing time and freeness.

Claims (1)

[Claims] 1. When biochemically decomposing and saccharifying cellulose materials, oxidation treatment is performed using air, oxygen or ozone in the presence of an alkali as a pretreatment,
Method for saccharification of cellulosic materials.