Purification and some properties of a β-glucanase from a strain,Trichoderma reesei GXC

β-glucanase was purified from a solid-state culture of Trichoderma reesei on wheat bran in three steps which comprised ammonium sulfate precipitation, Sephadex G-100 chromatography, and DEAE-Sephadex A-50 chromatography. The molecular mass was determined to be 35.21 kilodaltons by sodium dodecyl sulfate-12.5% polyacrylamide gel electrophoresis. The β-glucanase at low pHs was more stable than that at high pHs, and optimum pH was 5.0. The optimum temperature was 60°C, and β-glucanase was relatively stable at below 40°C for 60 min. The K m of the enzyme on β-glucan was 10.86 mg/ml, and the V max on β-glucan was 14286 μmol of glucose equivalents per mg of the pure enzyme per min. The β-glucanase activity was significantly inhibited by Fe 3+ ions, and was reduced in the presence of Cu 2+ ions, Mn 2+ ions and Mg 2+ ions at 5 mmol/L and 10 mmol/L, respectively. The β-glucanase activity was stimulated by Co 2+ ions, Ca 2+ ions, Zn 2+ ions, and Fe 2+ ions at 1 mmol/L and 5 mmol/L, respectively.