JPH11253152A - New acetan-degrading microorganism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new microorganism belonging to the genus Bacillus, having an acetan-degrading ability and useful for controlling a viscosity of a medium because the microorganism degrades the by-produced acetan when culturing a cellulose-producing microorganism to produce a bacterial cellulose. SOLUTION: This new microorganism is a strain belonging to the genus Bacillus and having an ability for degrading acetan, and exemplified by OTK strain (FERM P-16692) of a close species of Paenibacillus apiarius. The strain is obtained by carrying out a liquid enrichment culture and a plate culture, of a soil sample in order by using A-2 medium of pH 7.0, comprising 0.6% Na2 HPO4 , 0.3% KH2 PO4 , 0.5% NaCl, 0.5% NH4 Cl, 0.025% MgSO4 .7H2 O, 0.0004% vitamin B1 , 0.1% yeast extract, 0.1% acetan and 0.01% cycloheximide (an antifungal agent) respectively, further culturing the formed colony in a B-1 medium obtained by changing the acetan concentration of the A-2 medium into 0.5%, and screening the strain having a high acetan-degrading ability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel strain having acetan decomposability, and a method for decomposing acetan using the same.

[0002]

2. Description of the Related Art Cellulose producing bacteria such as BPR20
Acetobacte xylinum subspecies schlofermentans ( Acetobacte
r xylinum subsp. sucrofermentans ), Acetobacter xylinum ATCC 237
68, Acetobacter xylinum ATCC2376
9. Acetobacter pasteurianus ( A. pasteurianu)
s ) ATCC 10245, Acetobacter xylinum ATCC 14851, Acetobacter xylinum AT
CC11142 and Acetobacter xylinum ATC
When an acetic acid bacterium (genus Acetobacter) such as C10821 is cultured, it is found that the cross-sectional width of fibrils (or fine fibers) is about two digits smaller than that of cellulose produced from wood pulp or the like called bacterial cellulose (BC). The characteristic cellulose is obtained. Based on these structural features of bacterial cellulose, macromolecules, in particular,
There are various industrial uses as a reinforcing agent for aqueous polymers. For example, a substance obtained by solidifying such a disintegrated product of bacterial cellulose into a paper-like sheet or a solid form exhibits a high tensile modulus, and is expected to have excellent mechanical properties based on the structural characteristics of fibrils, and is used as various industrial materials. Have been.
Alternatively, it is also used as a filler retention agent in the papermaking process. In addition, bacterial cellulose is edible and tasteless and odorless, so it is often used in the food field, and because it has excellent water-based dispersibility, it maintains the viscosity of foods, cosmetics, paints, etc. It has industrial value for use as a food additive, water retention, food stability improvement, low calorie additive or emulsification stabilizing aid.

[0003]

In the conventional cultivation of cellulose-producing bacteria, acetan (AM-2) is produced as a by-product during the culturing process, and this acetan increases the viscosity of the medium. If the viscosity of the culture medium increases, the energy required for stirring the culture solution increases, and unfavorable situations such as a decrease in the ability to supply oxygen necessary for the growth of the cellulose-producing bacteria occur.

[0004]

Means for Solving the Problems In order to solve the above problems, the present inventors screened 117 kinds of soil samples in order to search for a strain having acetan degrading activity.
The present inventors have found a novel microorganism and completed the present invention. That is, the present invention relates to a strain belonging to the genus Bacillus and having acetan degradability. As a representative example thereof, for example, the OTK strain (FERM P-16692) can be mentioned.
The strain has been deposited on March 9, 1998 with the Patent Microorganisms Depositary of the Institute of Biotechnology and Industrial Technology, Ministry of International Trade and Industry of the Ministry of International Trade and Industry. The OTK strain of the present invention is an absolutely aerobic Gram-negative bacillus, and endogenous spores were confirmed. Further, a biochemical test and an assimilation test as shown in Table 1 below (A
From the results of the PI test), it is considered to belong to the genus Bacillus. However, Bergy's Manual of Systemat
Among the species described in ic Bacteriology, there was no strain whose properties completely matched those of the OTK strain of the present invention. Further, as a result of a homology search of the 16s rRNA sequence (National Institute of Genetics DDBJ database), the OTK strain of the present invention was 90.6% compared to Paenibacillus apiarius and Bacillus a
mylolyticus and 88.6%, Bacillus pabuti and 88.6%.
It showed 6% homology. Therefore, the OTK strain of the present invention has a Pa
It was determined to be a related strain of enibacillus apiarius. still,
Among the strains having the acetan decomposability of the present invention, the acetan decomposability varies to a certain extent, but all strains in which acetan decomposability is substantially recognized as compared to conventional strains are all within the scope of the present invention. It goes without saying that it is included.

[0005]

[Table 1]

Further, the present invention relates to a method for decomposing acetan in a medium, comprising adding and culturing the above-mentioned strain having acetan degradability. Therefore, when culturing a cellulose-producing bacterium to produce bacterial cellulose, by adding the acetan-degrading strain of the present invention and culturing the same together, the acetan by-produced in the culture of the cellulose-producing bacterium is decomposed, It is possible to suppress an increase in the viscosity of the medium.

[0007] The culturing of the bacterial cellulose-producing bacterium itself can be performed by a method known to those skilled in the art. Incidentally, the BPR2001 strain was deposited on February 24, 1993 at the Patented Microorganisms Depositary Center of the Institute of Biotechnology and Industrial Technology of the Ministry of International Trade and Industry (Accession No. FERMP-1346).
6) and subsequently transferred to a deposit under the Budapest Treaty on the International Recognition of the Deposit of Microorganisms for Patent Procedure on February 7, 1994 (Accession No. FERM BP-4545).

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the following examples. It is well known to those skilled in the art that such examples do not limit the scope of the present invention in any way.

[0009]

EXAMPLES Example 1 Screening of OTK Strain 117 soil samples were obtained at 30 ° C. using A-2 medium at 3 ° C.
Liquid enrichment culture for ~ 7 days, and then A-2 medium (1.5
% Agar) for 2 days at 30 ° C., the formation of 280 colonies was observed. These colonies were liquid-cultured at 30 ° C. for 48 hours using a B-1 medium (in which the acetan concentration in the A-2 medium was changed to 0.5%). The amount of sex acetane was measured by the Somogyi-Nelson method and the phenol sulfate method, which are well known to those skilled in the art. As a result, as an example having the highest acetan decomposability, an OTK strain capable of assimilating about 90% of the acetan added to the medium at 24 hours after the start of the culture was obtained. FIG. 1 shows the changes in the amounts of reducing sugars and water-soluble acetan in the medium in the liquid culture of the OTK strain.

[0010]

TABLE 2 A-2 medium composition _{Na 2 HPO 4 0.6 (%)} KH 2 PO 4 0.3 NaCl 0.5 NH 4 Cl 0.5 MgSO 4 · 7H 2 O 0.025 vitamin B ₁ 0. [0004] Yeast extract 0.1 Acetane 0.1 Cycloheximide (antifungal agent) 0.01 pH 7.0

Example 2 Purification of Acetane-Degrading Enzyme An attempt was made to purify acetan-degrading enzyme from the OTK strain. Purification was carried out to a specific activity of about 124 times. The results are shown in Table 3 below.

[0012]

[Table 3]

[0013]

According to the present invention, a novel strain capable of decomposing about 90% of acetan has been newly found. This strain degrades acetan produced as a by-product when culturing a cellulose-producing bacterium to produce bacterial cellulose, and thus can be used to suppress an increase in the viscosity of the medium.

[Brief description of the drawings]

FIG. 1 shows changes in the amounts of reducing sugars and water-soluble acetan in a medium in a liquid culture of the OTK strain of the present invention.

Claims (4)

[Claims] 1. A strain belonging to the genus Bacillus and having acetan degradability. 2. The strain having acetan degradability according to claim 1, which is a closely related strain of Paenibacillus apiarius. 3. OTK strain (FERM P-16692)
The strain having acetan degradability according to claim 2, which is 4. A method for decomposing acetan in a medium, comprising adding and culturing the strain having the ability to degrade acetan according to claim 1.