Abstract:

Bile salt hydrolase (BSH) produced by Lactobacillus acidophilus La-XH1 is able to hydrolyze conjugated bilesalts into free cholic acid, which can co-precipitated with cholesterol at low pH, thus leading to the removal of cholesterol.In this study, the bile salt hydrolase was separated and purified, and some of its enzymatic properties were studied. Resultsshowed that the specific activity of crude extract and purified enzyme by ammonium sulfate precipitation and DEAESepharoseCL-6B column chromatography was 47.82 and 115.85 U/mg, respectively, which corresponded to purificationfolds of 4.46 and 10.82 and recovery rates of 59.89% and 25.11%, respectively. The molecular weight of the purified enzymewas about 43 kD by SDS-PAGE. Its optimum temperature and pH were 40 ℃ and 6.0, respectively. Fe3+, Ca2+, Mg2+,Mn2+ and Zn2+ had activation effect on the enzyme, especially Fe3+. Na+ and K+ had no effect, but Cu2+ and Ba2+ had stronginhibitory effects on it.

Key words: Lactobacillus acidophilus, bile salt hydrolase, purification, enzymatic property