Study on Breeding of Bacillus Subtilis and Its Fermentation Process on Soybean Meal

[Objective] The study was to provide the theoretical basis for industrialized production of soybean peptides.[Method] B1-2 strain of Bacillus subtilis which was screened by UV mutation was taken to ferment soybean meal for producing soybean peptides.The optimum fermentation condition was determined through single factor and orthogonal tests.[Results] The effects of factors on fermentation ability of B1-2 strain of Bacillus subtilis on soybean meal for producing soybean peptides in order was soybean meal content,pH value of medium,fermentation temperature and inoculation amount.The optimum fermentation condition was as follows: contents of soybean meal and bran in fermentation medium were 9% and 2% resp.,B1-2 strain of Bacillus subtilis which was cultured for 24 h was taken as fermentation strain,initial pH value of medium was 7.5 and fermentation time was 64 h with fermentation temperature of 35-40 ℃ and inoculation amount of 8%.Under this condition,the hydrolysis degree of soybean meal protein was increased from 17.80% to 21.06%,being increased by 18%.[Conclusion] The study optimized the processing condition of Bacillus subtilis fermenting soybean meal for producing soybean peptides.