Isolation, identification and enzyme-producing capacity of Bacillus in fermented grains of sauce-flavor Baijiu

Bacillus strains were isolated from fermented grains of sauce-flavor (Jiangxiangxing) Baijiu by streak plate method and identified by morphological observation, physiological and biochemical tests, and 16S rDNA sequence analysis. The production capacity of protease, amylase and cellulase of the isolated strains was analyzed by plate transparent circle method and spectrophotometer, and the Bacillus with superior enzyme production performance was screened. The results showed that 15 Bacillus strains were isolated from the fermented grains of sauce-flavor Baijiu, numbered as JP1-JP15, all of which were gram-positive bacteria including 3 Bacillus subtilis, 1 Bacillus cereus, 4 Bacillus amyloliquefaciens, and 7 Bacillus licheniformis. The 3 B. subtilis with the stronger comprehensive enzyme-producing capacities were screened, numbered as JP2, JP9 and JP11, respectively. Among them, Bacillus JP11 had the strongest comprehensive enzyme production capacity, and its protease activity was 271.83 U/ml, amylase activity was 21.25 U/ml, and cellulase activity was 387.42 U/ml.