Sewage and sludge fermentation process of producing biopesticide bacillus thuringiensis

Abstract

The present invention relates to technology of utilizing waste in producing high efficiency biopesticide, sewage sludge with solid content of 1.5-5 % is used as the material for fermentation producing Bacillus thuringiensis (B.t). Sludge is filled into fermenting tank, pH regulated to 7.2, sterilized at 121 deg.c for 20 min and inoculated with B.t seed in 1-4 wt%. After aerobic fermentation at 28 deg.c and 200 rpm stirring for 30 hr, the fermented matter with cell number up to 10E9 and spore accounting for over 90 % is discharged. Sludge with rich organic carbon, nitrogen and inorganic salt is excellent medium for B.t to grow, and compared with culturing in soybean powder culture medium, the sewage sludge fermentation process has 10 hr shorter production period, higher biotoxicity of crystal cell mixture and 3 times lower cost.

Description

1. Technical field [0001] The invention relates to a method for producing bio-pesticide Bacillus thuringiensis by fermenting sewage sludge, which is a technology for producing high-efficiency bio-pesticide by using waste, and belongs to the field of environmental biotechnology. 2. Technical background [0002] Most sewage treatment plants in my country use the activated sludge method for sewage purification, and produce sewage sludge accounting for about 0.3-0.7% of sewage inflow while purifying sewage. The lack of suitable disposal outlets for these increasingly large and highly concentrated wastes has become one of the important factors that seriously plague the healthy development of my country's sewage treatment industry. [0003] On the other hand, the current use of chemical pesticides to control plant diseases and insect pests plays an important role in increasing agricultural production, but the residues of chemical pesticides are very harmful to the environment and ...

AI Technical Summary

Problems solved by technology

However, at present, the production of Bacillus thuringiensis preparations mostly uses high-priced agricultural and sideline products such as soybean powder, starch, and yeast extract as raw materials, and the production cost is relatively high, which limits the further promotion of Bacillus thuringiensis preparations. It is reported that the raw materials for Bacillus thuringiensis production account for the entire production 30-40% of the cost, therefore, choosing low-cost raw materials is the key to the commercial production of Bacillus thuringiensis preparations

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