虾酱源芽孢杆菌的筛选及其益生特性OACSCDCSTPCD

Five Bacillus strains were isolated from the traditional homemade shrimp paste,and were identified as Bacil-lus amyloliquefaciens Y11,Bacillus velezensis Y12,Bacillus subtilis Y13,Bacillus safensis Y32,and Bacillus cereus BI6Y.All five strains could grow normally at 10％NaCl concentration,had different protease and lipase and antibacterial substances production capacities.Among them,Bacillus cereus BI6Y has β-hemolysis and is insensitive to chlorampheni-col,vancomycin and norfloxacin,hence is not suitable for a probiotic.The other four Bacillus strains are y-hemolytic,insensitive to chloramphenicol,with a self-aggregation rate between 25％and 35％,and tolerant to acid and bile salts;they were found to secrete surfactin and could survive after treatment with artificial gastrointestinal fluid,the strain that had the highest survival rate in artificial gastric juice(pH 2.0)was found to be B.subtilis Y13(95.3％),and in artifi-cial intestinal juice it was B.safensis Y32(85.1％).The bacterial cell,cell-free supernatant,and cellular contents had different antioxidant activities,and the cell-free supernatant could scavenge 1,1-diphenyl-2-trinitrophenylhydrazine(DPPH)and hydroxyl radicals simultaneously,the scavenging rate is between 40％and 60％.The results of the study showed that in addition to B.cereus BI6Y,B.amyloliquefaciens Y11,B.velezensis Y12,B.subtilis Y13,B.safensis Y32 have certain safety and probiotic properties,hence could be used as potential probiotics,which would provide a theoretical basis for the development of Bacillus.spp-based probiotic products.