Two different methods for screening of bile salt hydrolase activity in Lactobacillus strains

Abstract

Bile salt hydrolase (BSH) activity of intestinal bacteria (including lactobacilli) is one of the indirect ways of decreasing a cholesterol level in human body. Tested Lactobacillus strains were isolated from various sources (faeces of fully breast-fed infants, cow’s colostrum, cow’s raw milk cheeses, and cow’s raw milk) and identified by genotypic and phenotypic methods. All strains, including three commercial probiotic strains and six culture collection strains, were subsequently tested for their BSH activity via two methods – thin layer chromatography (TLC) and plate assay. Among all the 59 Lactobacillus strains, 15 strains were shown to be BSH positive by TLC method and only 8 of them by plate assay. Most of the BSH positive strains (9 strains) were isolated from faeces. Differences between BSH activities for sodium salts of cholyltaurine and cholylglycine were demonstrated. The TLC method was shown to be more sensitive compared to the plate assay for BSH activity determination.