JPS6287097A - Production of ethanol using slightly decomposable plant biomass source as raw material - Google Patents

Abstract

PURPOSE:To obtain ethanol from the titled source in high efficiency, by immersing a slightly decomposable plant biomass source in a solution of a carboxylic acid peroxide, crushing it by a grinder to form a cellulosic substance, saccharifying it with cellulase and subjecting the saccharified substance to alcohol fermentation. CONSTITUTION:A slightly decomposable pant biomass source is immersed in a solution of a carboxylic acid peroxide (e.g., paracetic acid, etc.,) while or before grinding or the solution is poured into a grinder and the source is crushed to give a cellulosic substance, which is saccharified with cellulase and fermented with alcohol yeast or fermented while being saccharified, to give ethanol. The cellulosic substance obtained by grinding can be directly subjected to alcohol fermentation with a bacterium belonging to the genus Clostridium.

Description

[Detailed Description of the Invention] "Industrial Application Field" Since ancient times, many attempts have been made to produce glucose and ethanol using plant biomass resources that are abundant in nature and use them for food, industrial purposes, or energy. It has been done by people.

However, when using cellulosic plant biomass resources, the problem is the pretreatment method to make it easier for cellulase to act.

The present invention particularly relates to a method for producing ethanol from refractory plant biomass resources on which cellulase is difficult to act.

“Conventional technology” Conventionally, as a pretreatment method, a ball mill was used to reduce the particle size to 5.
There is a pulverization method that enlarges the reaction area by pulverizing the material to 0μ or less, but it has not been put to practical use yet because the power required for pulverization is large.

In contrast, a freeze-pulverization method has been proposed for the purpose of increasing the crushing efficiency and reducing the crushing power, but it has the disadvantage that the power required for freezing is large. In addition to this, a radiation irradiation method has been proposed as a physical treatment method.

Chemical pretreatments include a method of reducing the crystallinity of cellulose using phosphoric acid disulfuric acid and the like, and a method of delignification treatment using caustic soda and the like.

As a pretreatment method for plant biomass resources, the present inventors
I have been researching blasting treatment methods.

The blasting treatment method is used to reduce plant biomass resources to 15 to 40 kilograms.
g/c11! After steaming for several minutes with saturated steam, the pressure is instantly released and the material is released under normal pressure, and the material is destroyed by explosive volume expansion due to vaporization of water contained in the material and mechanical destruction caused by high-speed jetting from the nozzle. This is a method of crushing.

When herbaceous plants such as rice straw and bagasse, and broad-leaved trees such as poplar are treated with the above-mentioned blasting method, the hemicellulose in the plants is converted into its constituent sugars xylose, galactose, mannose, glucose, and other water-soluble j'4'! , becomes sugars.

In addition, lignin, which is insoluble in water, has ether bonds and C-C
Partial cleavage of bonds occurs, resulting in low-molecular-weight lignin that is soluble in organic solvents and dilute alkaline solutions. As a result, the cellulose that had been surrounded by lignin and hemicellulose is stripped bare and simultaneously pulverized by the high-speed jet described above. Therefore, cellulose pretreated by this blasting method is easily saccharified by cellulase. The present inventors have reported in the following literature a method for obtaining alcohol from [151] of the saccharified liquid obtained by this explosion method.

(ll Fermentation Engineering Society Lecture Abstracts, 1982, p. 179 (2); FY 1982, p. 233 (3)
)〃 1981, p. 143 (4) JP-A-59-204997 ``Problems to be solved by the invention'' However, as a result of further research on various types of wood, it was found that cedar, pine, fir, lauan, etc. It has been reported that the above blasting method has little effect on refractory plant biomass.

(Mitsuhiko Tanahashi: Summary of the Kyoto University Mokuken Public Lecture held on May 13, 1981) This is cellulose, which constitutes persistent plant biomass.
This is thought to be due to the fact that the chemical properties and physical structures of hemicellulose and lignin are different from those of herbs and broad-leaved trees.

Therefore, in the present invention, we promote the partial cleavage of ether bonds and carbon-carbon bonds in lignin of persistent plant biomass resources, make it easier for cellulase to act on cellulose, and produce ethanol using the obtained cellulose as a raw material. The technical challenge is to do so.

"Means for Solving the Problems" In order to solve the above technical problems, the present invention provides a method for blasting persistent plant biomass resources, in which the substance is treated with carboxylic acid peroxide during and/or before blasting. immersed in a solution;
and/or a method for producing ethanol, characterized in that the solution is injected into an explosion machine and the resulting cellulose is saccharified with cellulase or fermented with alcoholic yeast while being saccharified, and the cellulose that has been subjected to the pretreatment. the cross 1
- It consists of a method for producing ethanol characterized by direct alcohol intoxication with bacteria of the genus Lydium.

In the former method, cellulase is used to saccharify the yeast at about 45°C, and then the yeast, Romyces cerevisiae, is used.
Fermentation is carried out at ℃.

In the latter method, Clostridium bacteria, which are thermophilic anaerobic alcohol-intoxicating bacteria, are inoculated and incubated at high temperatures under anaerobic conditions at approximately 50 to 60 ml.
Ethanol is directly obtained from cellulose by culturing at 0'c) for 5 to 15 days.

Persistent plant biomass resources include cedar and pine.

Examples include conifers such as larch and broad-leaved trees such as lauan.

As the carboxylic acid peroxide, peracetic acid and perbenzoic acid are used, and in the case of the immersion method, the concentration of the solution is 0.1 to
10% and the immersion time is from 1 minute to 2 days. In addition, in the case of the injection method, the chemical solution is added to approximately 20% of the wood chips.
% amount into the blasting machine at the same time as the wood chips.

In addition, blasting is performed using 15 to 40 kg/c% of saturated steam.
It is preferable to carry out the test for 0 minutes.

"Example" The present invention will be explained below with reference to Examples.

(Example 1) After soaking pine chip material in 2% peracetic acid solution for 24 hours, 28 kg
/cal for 10 minutes. The blasted pine was washed with 10 times the volume of water, and 400 g of the obtained cellulose fraction and 20 g of cellulase, which is a mixture of meicelase (8000 U') and cellulosin AP at a ratio of 7:3, were added to a 0.05 M citrate buffer with a pH of 4.5. Liquid 2000++j! In addition, it was seasoned for 2 days with shaking in a constant temperature water bath at 40°C.

Add 20 g of ammonium sulfate and 1 yeast extract to the saccharification liquid as yeast aids.
Add 0g and add yeast Satucharomyces cerevisiae to 106
7m1. The seeds were inoculated and fermented for 7 days at 30"C. Water soaked pine was used as a control.

As a result of analyzing the fermentation liquid, the ethanol in the fermentation liquid made from crushed pine soaked in 2% peracetic acid was 5.2% (V), while that of pine soaked in water was 1.6% (V). there were.

(Example 2) After soaking cedar chips in 2% peracetic acid solution for 24 hours, 28 kg
/crA for 10 minutes. After washing the blasting material with 10 times the amount of water, it was added to DSM medium as a substrate at 1.0%, and p
After adjusting the temperature to l+ 7.0 and making it anaerobic with nitrogen gas, Clostridium spp., which is a thermophilic anaerobic alcoholic bacterium, was inoculated and cultured at 60°C for 18 days.The ethanol content in the medium was analyzed by gas chromatography. analyzed by
A comparison was made with water-immersed blasted crushed cedar.

This result shows that the ethanol in the fermentation mash obtained from the water-soaked blasting material was 0.03 (V)%, while the ethanol was 2%.
It is made from blasted cedar soaked in peracetic acid and has a voltage of 0.20 (V).
%, which is more than 6 times higher.

"Effects of the Invention" According to the present invention, it is possible to produce ethanol efficiently from refractory plant biomass resources. Edible plant biomass resources,
It is of great significance in opening the way to its use in industrial or energy applications, and makes a great contribution to this field.

Claims (1)

[Claims] 1. A method for blasting a refractory plant biomass resource, comprising: immersing the material in a carboxylic acid peroxide solution during and/or before blasting, and/or injecting the solution into a blasting machine; A method for producing ethanol, which comprises saccharifying cellulose obtained by blasting with cellulase or fermenting it with alcohol yeast while saccharifying. 2. In a method of blasting difficult-to-decompose plant biomass resources, the material is immersed in a carboxylic acid peroxide solution during and/or before blasting, and/or the solution is injected into a blasting machine to crush the cellulose material. A method for producing ethanol, which is characterized by direct alcohol fermentation using Clostridium bacteria.