Specificity, inhibitory studies, and oligosaccharide formation by beta-galactosidase from psychrotrophic Bacillus subtilis KL88.

beta-Galactosidase from psychotrophic Bacillus subtilis KL88 was specific to the beta-D-glycosidic linkage normally present in lactose. The enzyme was completely inhibited by transition metal ions (Cu2+, Fe3+, Fe2+, Zn2+) and partially inhibited by high concentrations of glucose and galactose as well as Ca2+. It was activated by most of the alkaline earth metal ions (NA+, K+, Li+). Oligosaccharides were formed at the different levels of lactose concentrations reaching more than 20% for high lactose concentration (20%). Three types of oligosaccharides were formed in significant concentrations detected by HPLC analysis.