KR0135498B1 - Process for preparing microbial pesticide b.t. by culturing - Google Patents

Abstract

The present invention is inoculated into Bacillus thurinngiensis spawn in a sterile semi-solid medium containing the protein as a main component and then cultured until the number of microbial cells reaches 108 to 1010 cells / g to produce BT toxin A method and a microbial insecticide produced by the method.

Description

Method for producing microbial insecticide B.T using semi-solid medium culture method

The present invention relates to a method for producing a microbial insecticide using a semi-solid medium culture method, and more particularly, to a microbial insecticide B, T. agent having a high insecticidal properties against larvae of lepidoptera, flies, and mosquitoes.

In recent years, with increasing global interest in environmental pollution, the use of toxic pesticides has become increasingly regulated, and interest in the development of low-toxic and non-toxic biopesticides is increasing. It has long been used for more than 30 years, but is known to be safe microbial insecticide B.T. Research on the agent is becoming active. These B.T. The agent is produced by a microorganism called Bacillus terringiensis, which is commercially produced in large quantities by liquid culture in large fermenters. For example, after inoculating Bacillus turinggissis seed in a liquid medium and incubated in a large fermenter for 3-5 days, the cells and B.T. A process for recovering protein crystals can be used. The large fermentation tanks and microbial recovery systems used in these processes require a lot of installation cost, and also require a high level of expertise for operation. Therefore, this method is a large risk for SMEs. In conclusion, in order to solve the difficulties of cheap facility investment and supply of professional manpower, simple and small-sized production technology is needed. Among the methods that can be easily applied on a small scale in the cultivation of microorganisms, there is a semi-solid culture method that has been used in the process of making yeast and meju traditionally for a long time. With this in mind, the present inventors have adjusted the beneficial medium for the production of insecticide crystals of Bacillus terringensis without using soybeans by utilizing the properties of soybean-like Bacillus terringiensis and the particularly economical semi-solid culture method. BT grows economically by increasing the total number of microorganisms by about 10 times than when growing in medium. To be able to produce

That is, the present invention is inoculated and cultured Bacillus terringiensis spawn in a sterile semi-solid medium, when the number of cells (spores) reaches 108 to 1010 cells / g and dried to powder at 50 ℃ or less to produce a BT agent The main components of the semi-solid medium of the present invention are boiled soybeans, soybean meal, rapeseed meal, etc., which are rich in protein and relatively inexpensive, and include molasses, glucose, sugar, and corn as growth promoters of microorganisms. A small amount of syrup, corn leachate, yeast powder, etc. may be added, and a little byproducts of agricultural products such as rice bran, sawdust, wheat flour, etc. may be added to improve breathability during microbial culture.

Glucose, sugar, molasses, corn test, etc., added to promote the short-term growth of microorganisms are used in small amounts, that is, 1 to 10% by weight based on the weight of the microbial medium, and corn leachate, yeast powder, etc. 1 to 5% by weight may be added as a standard. Rice bran, bran, sawdust and the like may be used in an amount of 10 to 20% by weight based on the weight of the medium to improve breathability.

Specifically, the production method of the BT agent of the present invention is mixed with soybean, soybean meal or rapeseed, optionally microbial growth promoter and rice bran, sawdust or bran, and after the mixture is boiled or sterilized, Bacillus terringiensis spores After inoculating 106 cells / g in protein medium, the cells are incubated for 2 to 7 days in a 20 to 30 ° C. culture chamber. At this time, the water content of the semi-solid medium is maintained at 50 to 60%, the thickness of the semi-solid medium is maintained at less than 10cm, supplying oxygen or venting the produced gas by aeration. After 3 to 5 days of culture, the number of cells of Bacillus terringiensis reaches 109 to 1010 cells / g, wherein many cells are B.T. Forms toxins. The semi-solid medium containing Bacillus terringiensis thus produced is dried at room temperature or below 50 ° C., and then powdered to obtain a B.T. insecticide that exhibits strong insecticidal properties against lepidoptera insects such as larvae of moths. In particular, the composition of soybean-based medium was the growth of Bacillus teringiensis and B.T. Suitable for toxin production These production methods are suitable for use by SMEs due to the advantages of simplicity of production facilities, small-scale facility investment, cheap raw materials, and low-tech manpower.

Hereinafter, the present invention will be described by Examples, but the present invention is not limited to these Examples.

Example 1

1000 gm of beans, 50 gm of glucose, and 100 gm of rice bran were added to 2000 cc of water and boiled until the beans were soft enough.

These were ground to form a semisolid medium, and then cooled at room temperature. About 106 cells / g Bacillus terringiensis spores were inoculated into the medium and then incubated on a tray at a thickness of 5 cm, and the incubation temperature was adjusted to a range of 25 to 30 ° C. and maintained at a relative humidity of 90%. After incubation for about 5 days, the microbial count and B.T. Crystal formation was observed under a microscope. From around 3 days B.T. Crystals formed. After incubation for 5 days, the microbial count reached about 109 cells / g. These results demonstrate that the inexpensive production process of the present invention can achieve microbial growth at about the same level as the liquid culture method.

Example 2

Microbial cultures containing Bacillus terringiensis cells produced in Example 1 were dried and powdered. When these powders were diluted to 1/10, 1/100, 1/1000, and the like, they were treated to cabbage moth larvae and showed 100% insecticidal effect after 48 hours until the 1/100 dilution. The results demonstrate that the product possesses commercially available pesticides.

Claims (6)

Bacillus thuringiensis spawn was cultured in B.T. How to produce toxins. The method of claim 1, wherein the legume protein is one or more boiled or sterilized selected from soybean, soybean meal and rapeseed gourd The method of claim 1, wherein the semi-solid medium further comprises 1 to 10% by weight of at least one component selected from glucose, sugar, molasses and corn syrup. The method of claim 1, wherein the semiconductor medium further comprises 1 to 5% by weight of corn leachate or yeast powder. The method of claim 1, wherein the semiconductor medium is a feather characterized in that it further comprises at least one component selected from 10 to 20% by weight of rice bran, bran and sawdust. B.T. produced by claim 1. Microbial insecticide containing toxin as an active ingredient.