Bile salt hydrolase activity of three strains of Lactobacillus acidophilus

Three strains of Lactobacillus acidophilus, two from human intestinal origi n (016 and L1) and one from porcine intestinal origin (ATCC 43121), were te sted for their bile salt deconjugation activity. The L. acidophilus ATCC 43 121 had more deconjugating activity of both sodium glycocholate and sodium taurocholate at pH 6.5 than did either L. acidophilus 016 or L1. The activi ty of intracellular bile salt hydrolase found in strain ATCC 43121 was 14-f old higher than that in either of the other two strains. The optimum pH for deconjugation of sodium glycocholate was between 4 and 5.5 for all three s trains. For deconjugation of sodium taurocholate, the optimum pH was betwee n 3.5 and 4.5 for strains L1 and ATCC 43121 and was between pH 5 and 6 for strain O16. The molecular mass of the enzyme in all three strains of L. aci dophilus was estimated to be 126 kDa by Sephadex G-200 gel filtration. All three strains exhibited more bile salt hydrolase activity towards sodium gl ycocholate than towards sodium taurocholate.