[Selection of beta-glucanase-producing Trichoderma köningii T199 and its fermentation conditions]

A mutant strain T199 producing about 8 times as much beta-glucanase as its parent strain trichoderma köningii T3 was obtained by treatment with ultraviolet light and N-methyl-N-nitro-N-nitrosoguanidine. Fermentation was conducted in 250 mL flask, each containing 30 mL of medium consisted of 5% corn cob powder, 3% wheat bran and 1.4% nitrogen source No. 10 ((NH4)2SO4 10%, Peptone 20%, Yeast extract 15%). The optima culture conditions were as below: initial pH 5.0, 30 degrees C, shaking speed 280 r/min, and cultivation time 5 d. Enzyme activity toward CMC-Na, lichenin, laminarin and barley beta-glucan at pH 5.0 and 60 degrees C for 10 min were 300, 1100, 12 and 1600 IU/mL, respectively. The optima pH and temperature for enzyme action toward barley beta-glucan were pH 5.0 and 70 degrees C, respectively. The enzyme was stable under below 50 degrees C and at pH 4.5-6.5.