<italic>Lactobacillus casei</italic> group is commonly used as probiotics. Various factors affect their viability in gastrointestinal tract. Twenty two strains of <italic>Lactobacillus casei</italic> group, were assessed for acid tolerance attribute. ASCC 292 showed the highest viability at pH 1.5. Fifteen remaining strains have shown no activity after 1 h. At pH 2.0, ASCC 1002 has shown lowest viability after 2 h of incubation. At pH 2.5, all twenty two strains decreased their viable count after 3 h of incubation. Greater viable count of <italic>Lactobacillus</italic> strains were observed at pH 3.0. This study suggests the importance to identify all the useful <italic>Lactobacillus</italic> strains in order to study further for their therapeutic benefits.

Lactobacillus casei group is commonly used as probiotics. Various factors affect their viability in gastrointestinal tract. Twenty two strains of Lactobacillus casei group were assessed for bile tolerance and deconjugation attribute. All strains had shown moderate activity at 0% bile concentration. At 1% bile concentration CSCC 2607 has shown highest growth while remaining Lactobacillus strains have shown fair growth. At 1.5% bile concentration only seven Lactobacillus strains showed growth and ASCC 1521 showed highest activity. All seven strains were able to deconjugate both sodium glycocholate and sodium taurocholate at varying levels. ASCC 1520 showed lowest deconjugation activity for sodium glycocholate. All seven strains showed lower deconjugation of sodium taurocholate compared to sodium glycocholate. ASCC 290 was least capable of deconjugation of sodium taurocholate. When mixture of sodium glycocholate and sodium taurocholate having the similar molar ratio in human bile, was taken, all seven strains showed consistent cholic acid secretion. ASCC 1521 also showed highest cholic acid liberation while ASCC 1520 showed lowest deconjugation ability. This study suggests the importance to identify all the useful Lactobacillus strains which are able to tolerate and deconjugate, high bile concentration in order to study further for their therapeutic benefits.

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