Abstract:Seven strains of bacteria were isolated from traditional Cupei and tested for in vitro probiotic function as well as their effect on the longevity of Caenorhabditis elegans (C. elegans). The strains differed significantly in terms of hemolytic ability, antibacterial activity, protease production, self-aggregation and co-aggregation, hydrophobicity, and DPPH free radical scavenging ability. Two strains of Rummeliibacillus stabekisii, CY2 and CY4, were selected based on no hemolysis and high protease content (11.49 mm and 13.24 mm), strong 24-h self-aggregation and co-aggregation ability, outstanding 24-h cell surface hydrophobicity, and good DPPH free radical scavenging ability (supernatant 48.69% and 59.22%, bacterial cell 44.00% and 41.20%). The results of acid resistance experiments showed that CY2 had significantly better acid resistance at pH value 3.0 than did CY4 and was able to multiply and grow; the survival rate increased by 8.82% at 4~8 h. CY2 also showed a high LPS degradation ability (46.95%). The results of the C. elegans lifespan experiment showed that CY2 could significantly prolong lifespan. Compared with the OP50 group, the average lifespan was prolonged by 1.37 days, the prolongation rate was 15.91% (P<0.05), and the maximum lifespan was extended by 1.00 d. Mixed feeding with OP50 prolonged the average lifespan by 1.47 d, the prolongation rate was 17.10% (P<0.05), and the maximum lifespan was prolonged by 2.00 d. These results indicated that R. stabekisii CY2 has signficant prebiotic properties and good development potential. The results of this study provide a reference and basis for exploring potential probiotics from new food sources.
