Influence of Bile on B-galactosidase Activity of Lactobacillus Bulgaricus

In the presence of 0.15% oxgall, the B-galactosidase activity of whole cells of Lactobacillus bulgaricus was increased. However, higher concentrations of oxgall decreased the enzyme activity. In the absence of oxgall, little or no B-galactosidase was exhibited by the whole cells. When the cells were lysed to obtain cell-free extracts prior to assay, there was some decrease in activity of the enzyme in the presence of 0.15% oxgall. Increasing concentrations of oxgall did not further reduce the activity. Apparently, the oxgall increases the permeability of the cells upto a certain concentration (0.15%) to allow more substrate to enter, resulting in more hydrolysis of the substrates. However, at concentrations higher than that, the enzyme activity was inhibited by the oxgall.