Production, Purification and Characterization of β-glucosidase from Bacillus subtilis strain PS Isolated from Sugarcane Bagasse

The effect of various carbon sources on extracellular beta-glucosidase (BGL) production and its catalytic activity with different substrate was analyzed in Bacillus subtilis strain PS isolated from sugarcane bagasse. The highest extracellular enzyme activity was obtained in minimal medium with supplement of glucose was higher 0.42 U/ml, compared to other carbon sources such as maltose, cellobiose, lactose and xylose. Extracellular BGL was partially purified to 18.04 fold with specific activity 17.32 U/mg using Sephadex G-75 gel filtration chromatography after dialysis of 70% ammonium sulfate precipitation. In gel filteration fractions, three peaks having beta-glucosidase activity and represents isozymes of beta-glucosidase with molecular weight of 193 kDa, 64 kDa and 42 kDa, respectively. Purified BGL showed catalytic activity with lactose, cellobiose, pNPG and mellibiose.