| dc.description.abstract | Lactose intolerance was a problem faced by a large proportion of the world's population. These problem could be alleviated by hydrolyzing lactose to glucose and galactose by β-galactosidase. β-Galactosidase occurred widely in nature and it was produced by a number of microorganisms. However, their characteristics were very different and it varied with the source of microorganism. The aim of this study was purification and characterization of β-galactosidase L. plantarum B 123. β-Galactosidase was extracted and partially purified by ammonium sulfate precipitation and dialysis. These steps resulted a purification level of 7.61 fold, a yield of 10.67%, and a specific activity of 61.53 U/mg protein. Optimum temperature and pH for dialyzed β-galactosidase were optimized at 50 °C and 7.0, respectively. Metal ions of Mg2+, Mn2+, Co2+, and Zn2+ in 10 mM stimulated the activity of crude β-galactosidase, while metal ions of Cu2+, Hg2+, and Ca2+ in 10 mM inhibited the activity of crude β-galactosidase. KM and Vmax for this dialyzed β-galactosidase were 1.13 mM and 7.25 U/mL, respectively. | en |
