In Vitro Bile Salt Hydrolase (BSH) Activity Screening of Different Probiotic Microorganisms

Bile salt hydrolase (BSH) activity in probiotic strains is usually correlated with the ability to lower serum cholesterol levels in hypercholesterolemic patients. The objective of this study was the evaluation of BSH in five probiotic strains of lactic acid bacteria (LAB) and a probiotic yeast. The activity was assessed using a qualitative direct plate test and a quantitative high-performance thin- layer chromatography assay. The six strains differed in their BSH substrate preference and activity. Lactobacillus plantarum DGIA1, a potentially probiotic strain isolated from a double cream cheese from Chiapas, Mexico, showed excellent deconjugation activities in the four tested bile acids (69, 100, 81, and 92% for sodium glycocholate, glycodeoxycholate, taurocholate, and taurodeoxycholate, respectively). In the case of the commercial probiotic yeast Saccharomyces boulardii, the deconjugation activities were good against sodium glycodeoxycholate, taurocholate, and taurodeoxycholate (100, 57, and 63%, respectively). These last two results are part of the novelty of the work. A weak deconjugative activity (5%) was observed in the case of sodium glycocholate. This is the first time that the BSH activity has been detected in this yeast.

Investigation of bile tolerance and deconjugation ability of various Lactobacillus Casei group strains

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.