Short communication: Detection and expression analysis of the bile salt hydrolase gene in pediococcus and lactobacillus

Bile salt hydrolase (BSH) has been considered an important enzyme that is produced in response to bile stress. The bsh gene reportedly encodes BSH in lactic acid bacteria. Thus, the aim of this study was to detect and measure the changes in bsh gene expression in Pediococcus pentosaceus M103, Lactobacillus casei AP, Lactobacillus casei AG, and Lactobacillus paracasei M104. A BSH primer was used in amplifying the bacterial genomic DNA, and the obtained amplicon was then sequenced and analyzed in order to detect genes homologous to bsh. Changes in expression levels were measured in three concentrations of bile salts: 0.1, 0.3, and 0.5 (w/v). The BSH primer produced amplicons 850 to 950 kb in length. Amino acid sequences from the amplicons were determined to be similar to the product sequence of BSH. The level of expression of the bsh gene was altered in every concentration of bile salts in the growth medium with bsh genes from P. pentosaceus M103 were induced by bile salts at concentrations of 0.1 and 0.3 (w/v). We conclude that P. pentosaceus M103 may make suitable probiotic candidates that can tolerate conjugated bile acids.