Molecular Cloning and Characterization of Bile Salt Hydrolase from Lactobacillus gasseri ATCC 33323 Strain

ABSTRACT

Bile salt hydrolase (BSH) active probiotic strains are being used in the treatment of hypercholesterolemia related diseases. Understanding the mechanism of action of the BSH of probiotics is crucial. Even though Lactobacillus gasseri is probably one of the most beneficial probiotics on the market, there is no information on the catalytic activity and substrate preferences of its BSH. This study aims to detect the substrate specificity of the BSH of Lb. gasseri ATCC 33323 strain, to determine the optimum temperature and pH of the BSH’s activity by ninhydrin assay. To do so, the BSH gene from Lb. gasseri ATCC 33323 was cloned into Escherichia coli XL1-Blue strain, expressed and characterized in E. coli BLR(DE3). Results indicated that even though the recombinant BSH (rBSH) was able to hydrolyze the six major human bile salts, there was an obvious preference for the glycine-conjugated bile salts and the maximum activities of the rBSH were recorded.

KEYWORDS:

• Bile salt hydrolase
• Lactobacillus gasseri
• probiotics
• substrate preference