[Screening and identification of probiotic bifidobacterium from Mongolian children]

Abstract

Objective: Bifidobacterium has important physiological activity in gastrointestinal tract of human and animals, and the tolerability of acid, intestinal juice and oxgall bile salt are the key factors that influence the function of living bacteria preparation. In this study, feces of 12 healthy Mongolian children were selected to isolate Bifidobacterium with probiotic properties.

Methods: Bifidobacterium was isolated from feces by selective medium and identified by physiological biochemical test. The tolerability of acid, intestinal juice and oxgall bile salt of 11 Bfidobacteria were studied and B. animalis V9 was identified further by molecular biological approach 16S rDNA.

Results: Eleven Bifidobacteria isolated from feces of 12 healthy Mongolian children were identified as B. adolescentis (A1, H3, G4, A8 and V10), B. longum (C6, C7 and D11), B. pseudocatenlatum (B2), B. bifidum (G5), B. animalis (V9). B. animalis V9 had the best acid tolerance with the survival rate 92.4% in artificial gastric juice at pH2.0 for 3h, whereas others had lower than 31.25%. B. animalis V9 also had good survival rate (99.7%) in artificial intestinal juice at pH8.0 for 8h after anaerobic cultured 3h in artificial gastric juice at pH2.0, and tolerated oxgall bile salt at concentration of 0.3%. B. animalis V9 was identified further by molecular biological approach 16S rDNA and result showed the homologies of B. animalis V9 was 99% with Bifidobacterium animalis subsp. lactic BB12.

Conclusion: B. animalis V9 had good probiotic properties to be potentiallyused in dairy products and health products.