JPH11299479A - Microorganism capable of solubilizing cellulosic substance and its utilization - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the new microorganism: Bacillus sp. 9-3 FERM P-15955, belonging to the genus Bacillus, having an ability to solubilize cellulose, and capable of easily solubilizing the cellulosic substance to produce useful substances. SOLUTION: This new Bacillus sp. 9-3 FERM P-15955 has an ability to solubilize cellulose, belongs to the genus Bacillus and is useful for solubilizing the cellulosic substance to produce useful substances. Filter paper, avicel (crystalline cellulose), toilet paper, copy paper, corrugated cardboard, etc., as the cellulosic substances are solubilized by the use of the Bacillus sp. 9-3., and the solubilization of the cellulosic substances is recognized on the basis of the amount of total organic carbon(TOC) contained in the supernatant of the culture liquid. The microorganisms are obtained by isolating from human waste sludge and subsequently culturing the isolated microorganism.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a microorganism for solubilizing a cellulosic substance, a method for solubilizing a cellulosic substance by the microorganism, and a method for solubilizing a cellulosic substance to produce a useful substance.

[0002]

2. Description of the Related Art Cellulosic resources are the most abundant organic substances on the earth and are widely used in building materials, clothing, paper and the like. In recent years, the problems of food shortages and energy crises have been highlighted in connection with population growth and increased energy consumption, and effective use of biomass such as cellulose has attracted attention as a solution to these problems. At present, about one-third of wood consumed in Japan is used as paper and fiber. After use, some is reused, but most is discharged as municipal waste. Many of them are mainly incinerated, but although incineration uses a part of the heat of combustion, it causes problems such as air pollution, so treatment methods, and methods for recycling and effective utilization are being studied. I have.
Paying attention to paper waste among cellulosic wastes, in recent years, the amount of paper waste generated in offices and offices has been increasing year by year, and its disposal has become a problem. Although the paper waste is partially reused as described above, most of the waste is incinerated and causes problems such as air pollution. Therefore, reduction of the amount of paper waste is a problem. The main component of paper waste is cellulose, and if this can be solubilized, the amount of paper waste generated can be significantly reduced. Further, it is possible to produce useful substances by decomposing and solubilizing cellulose.

[0003] As a method for solubilizing a cellulosic substance, there are a chemical method using an acid, a biological method using a microorganism, and the like. The method of hydrolyzing with an acid is used under severe conditions of high pressure, high temperature and strong acid. Because of the processing below, biological methods that are milder and cheaper than chemical methods,
Currently, it is mainly studied. Conventional biological methods include a method in which a microorganism is solubilized by a cellulolytic enzyme secreted outside the cells, and a method in which a cellulolytic microorganism is directly made to act on a cellulosic substance to be solubilized. In any of these methods, cellulose is a hardly decomposable substance that is hardly decomposed by microorganisms or enzymes produced by microorganisms due to its crystal structure, and hinders solubilization of paper waste and the like.

As a method for producing a useful substance from a cellulosic substance, a method has been studied in which cellulose is solubilized by the above-mentioned cellulose-decomposing enzyme and then fermented by a microorganism to convert it into a useful substance such as an alcohol or an organic acid. . However, production of cellulolytic enzymes for solubilization is costly, and solubilization and fermentation are required.
This is a stepwise reaction and has problems such as the need for reaction control. There is also a method of producing a useful substance directly from cellulose using a cellulolytic microorganism. However, in this method, since the cellulosic substance is a hardly decomposable substance, its resolution is a problem.

[0005]

SUMMARY OF THE INVENTION The present invention solves such problems in the prior art and provides a cellulose-based material which can easily solubilize a cellulose-based material and can be converted into a useful material. It is an object to provide a microorganism to be solubilized, a method for solubilizing a cellulosic substance using the microorganism, and a method for producing a useful substance from the cellulosic substance using the microorganism.

[0006]

Means for Solving the Problems The present inventors have conducted various studies in order to solve the above-mentioned problems, newly solubilizing a cellulosic substance, reducing the amount of cellulosic waste and producing useful substances. A novel microorganism was found, and the present invention was completed. That is, the present invention relates to Bacillus sp. 9-3 which is a microorganism of the genus Bacillus having a cellulose solubilizing ability.
(Bacillus sp. 9-3) FERM P-15555 (hereinafter, referred to as Bacillus sp. 9-3) and a cellulosic substance are immersed in a medium containing Bacillus sp. A method for solubilizing a cellulosic material characterized by decomposing, and culturing by immersing the cellulosic material in a medium containing the Bacillus sp. 9-3 to separate useful substances such as generated alcohols and organic acids. This is a method for producing a useful substance from a cellulosic substance.

[0007] Bacillus sp. 9-3, which is a microorganism of the genus Bacillus having the ability to solubilize cellulose according to the present invention, comprises:
The present inventors have found, isolated and cultured from night soil sludge, and deposited as a microfabrication laboratory No. 15955 (FERM P-15955) with the Research Institute of Microbial Industry and Technology, as shown in Table 1. It has various bacteriological characteristics.

[0008]

[Table 1]

[0009]

[Table 2]

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Cellulose-based substances are immersed and cultured in a suitable medium such as the medium shown in Table 1 containing Bacillus sp. The system material is decomposed and dissolved. The decomposition product is a mixture of saccharides, furthermore, alcohols, organic acids, etc. in which the saccharides are decomposed, and useful substances such as alcohols, such as ethanol, and organic acids, such as acetic acid, are separated from these by an appropriate method. Can be obtained. It is known that acetic acid is used as a substrate for methane bacteria and is converted to methane, and the acetic acid obtained can be converted to methane by using this method and used.

By applying the solubilization of a cellulosic substance by a microorganism of the genus Bacillus to cellulosic waste such as various paper wastes, the amount of waste can be significantly reduced. In addition, since the decomposition products contain useful substances such as alcohols and organic acids, they can be separated, collected and used effectively, and the cellulosic waste can be recycled. In addition, useful materials can be produced using not only waste materials but also various cellulosic materials as raw materials.

[0012]

The present invention will be described more specifically with reference to the following examples. (Example 1) Bacillus, a novel microorganism according to the present invention
A test for solubilization of various cellulosic substances was performed using SP 9-3. Filter paper, Avicel (crystalline cellulose: manufactured by Merck), toilet paper, copy paper and cardboard paper were used as the cellulosic material. 80 ml of the liquid medium having the composition shown in Table 2 containing these cellulosic substances was put into a vial having a volume of 100 ml, sealed, and autoclaved at 121 ° C. for 20 minutes. The above strain was inoculated into this sterile medium (initial cell protein 10 μg / ml), and 3
The culture was allowed to stand at 7 ° C. The initial pH of the liquid medium is 7.5,
No pH control was performed during the culture. As the culture is continued, the cellulose is solubilized and elutes in the solution. Therefore, the amount of solubilized cellulose was determined from the amount of total organic carbon (TOC) contained in the supernatant of the culture solution. That is, after the start of the culture, sampling is performed over time under anaerobic conditions (after 0, 1, 3, 5, and 9 days have elapsed after the start of the culture), the sampled liquid is centrifuged (20,000 g × 5 minutes), and the supernatant is added to the supernatant. The contained TOC amount was measured. TOC measurement is Shimadzu TOC-
500. The shape of the paper used is not affected, and the paper may be immersed in a liquid medium.

FIG. 1 shows the results of the TOC measurement. In FIG. 1, the horizontal axis indicates the number of days of culture, and the vertical axis indicates the concentration of TOC. In addition,
For the cellulose-free sample used as a control, the TOC increase was not observed or was very slight for any cellulose. Degradation was confirmed in any of the cells to which the bacteria were added, indicating that the microorganisms are effective in solubilizing the cellulosic substance.

Example 2 FIGS. 2, 3 and 4 show the results of continuing the culture test using a culture solution containing copy paper, cardboard paper and toilet paper of Example 1 for up to 17 days, respectively. From the increase rate of TOC in these test results, the decomposition rate of each paper (the value obtained by dividing the TOC increased between the third and fifth days of culture by the number of days, that is, 2) is 0 for copy paper. 0.6 g / L /
d, 0.1 g / L / d for cardboard paper and 0.7 g / L / d for toilet paper. When the TOC became almost steady, about 80% was decomposed in the case of copy paper and toilet paper, and about 20% remained as a residue.

Example 3 In a culture test using a culture solution containing Avicel (crystalline cellulose: manufactured by Merck) in Example 1, sampling was performed on days 0 and 11 of the culture elapsed time. Centrifugation (20
000 g × 5 minutes), and the amounts of organic acids and alcohols in the supernatant were measured by gas chromatography analysis. Tables 3 and 4 show the gas chromatography analysis conditions, and Table 5 shows the analysis results. As a result of analysis, 1 g of cellulose was added to 0.1 g of acetic acid.
It was found that 5 g and 0.07 g of ethanol could be produced. Of the carbon (43%) that could not be recovered, 3
0% was accumulated in the gas phase.

[0016]

[Table 3]

[0017]

[Table 4]

[0018]

[Table 5]

[0019]

According to the present invention, Bacillus sp. 9-3, a Bacillus microorganism having the ability to solubilize cellulose according to the present invention.
(Bacillus sp. 9-3) FERM P-15555 can efficiently solubilize various cellulosic substances. By using the microorganism of the genus Bacillus, various cellulosic substances such as copy paper, filter paper, cardboard paper, and toilet paper can be solubilized, and the amount of various cellulosic wastes can be reduced. In addition, by decomposing and solubilizing various cellulosic substances, useful substances such as alcohols and organic acids can be produced, and various cellulosic wastes can be recycled and useful substances from biomass, which is currently not used effectively, can be produced. Becomes In particular, since the copy paper can be disassembled and solubilized, the amount of paper waste mainly composed of copy paper discarded from offices and offices can be reduced and recycled, and its practical value is great. There is something.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the elapsed days of culture and TOC in Example 1.

FIG. 2 is a graph showing the relationship between the elapsed days of culture and TOC for copy paper in Example 2.

FIG. 3 is a graph showing the relationship between the elapsed culture days and the TOC for cardboard paper in Example 2.

FIG. 4 is a graph showing the relationship between the elapsed culture days and TOC for toilet paper in Example 2.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C12R 1:07) (C12P 7/10 C12R 1:07) (C12P 7/54 C12R 1:07)

Claims (4)

[Claims] 1. A Bacillus sp. 9-3 (Bacillus sp.) Which is a microorganism of the genus Bacillus having a cellulose solubilizing ability.
sp. 9-3) FERM P-15955. 2. A Bacillus sp. 9-3 (Bacillus) which is a microorganism of the genus Bacillus having a cellulose solubilizing ability.
sp. 9-3) A method for solubilizing a cellulosic substance, comprising immersing the cellulosic substance in a medium containing FERM P-15955, and culturing the microorganism of the genus Bacillus to decompose the cellulosic substance. 3. Bacillus sp. 9-3 (Bacillus sp.), A microorganism of the genus Bacillus having a solubilizing ability for cellulose.
sp. 9-3) Cellulose-based material characterized by immersing a cellulosic material in a medium containing FERM P-15955, culturing the microorganism of the genus Bacillus to decompose the cellulosic material, and separating the produced useful substance. A method for producing useful substances from substances. 4. The method for producing a useful substance from a cellulosic substance according to claim 3, wherein the useful substance is acetic acid or alcohol.