Influence of Bile on β-Galactosidase Activity and Cell Viability of Lactobacillus reuteri when Subjected to Freeze-Drying

Abstract

The effect of bile on β-galactosidase activity and cell viability was investigated using two strains of Lactobacillus reuteri that were subjected to freeze-drying. In the presence of 0.15% oxgall, β-galactosidase activity of the whole cells was significantly increased. After lyophilization, the cultures that had been treated with oxgall showed a low survival rate without changes in β-galactosidase activity. The poor resistance of the cells to damage from freeze-drying might be related to the presence of membranous structures containing simple folds and buds of the cell membrane, as was observed by transmission electron microscopy.