Properties of β-Galactosidase from Lactobacillus salivarius subsp Salivarius Nam27

Lactobacillus salivarius subsp. salivarius Nam27 with a high P-galactosidase activity was selected for enzymatic characterization. For purification, cell pellet was disrupted by Bead Beater, by DEAE-Sepharose and Mono-Q chromatography. The specific activity of the purified enzyme was 5,312 units/mg. The molecular weight of native monomeric beta-galactosidase was estimated to be 30,000 dalton (monomer) by the SDS-PAGE. The optimum temperature and optimum pH were 50 degrees C and 5.0, respectively. This enzyme was stable between 35 and 55 degrees C. P-Galactosidase activity was lost rapidly above pH 7.0. But beta-Lyalactosidase was more stable at pH 4.0 (acidic conditions). And beta-galactosidase activity was lost rapidly above 65 degrees C after 10 min incubation. Ca2+ and Zn2+ metal ions enhanced beta-galactosidase activity by 164.09% and 127.37%, while Cu2+, Fe3+ and Mn2+ lowered beta-galactosidase activity by 58.29%, 85.10% and 77.66%, respectively. Other metal ions didn't affect P-galactosidase activity significantly.