Purification and kinetics study of thermostable cellulase free xylanase from Bacillus subtilis

Present study dealt with the production, purification and characterization of xylanase from Bacillus subtilis- BS05 grown in submerged fermentation at 37(o)C for 48h using sugarcane bagasse as a substrate. Xylanase enzyme was purified to homogeneity by ammonium sulphate fractionation followed by sephadex G-100 chromatography. The molecular mass of xylanase enzyme was found to be 23kDa by SDS-PAGE. The optimum pH and temperature of xylanase enzyme was 5 and 50°C with stability range of 5-6 and 30°C -50°C respectively. The enzyme had half life of 1386-1155 minutes at 30°C -50°C respectively. Metal profile of the enzyme showed that Mn(2+) (127.4 %) and Fe(2+) (115%) were the activators while Hg(2+) (14%) and EDTA (19%) were the inhibitors. Kinetic parameters revealed that the enzyme is specific to birchwood xylan with Km , Kcat , Vmax and Kcat/Km value of 1.15 mg/ml, 850 s(-1), 117.64 U/mg and 739.13 s(-1)mg(-1).mL respectively.