Screening of high-yield xylanase-producing Actinomycete sp. and optimization of its fermentation conditions

52 actinomycetes were isolated from the soil samples of different districts of China based on plate screening method, and 12 strains was obtained with enzyme activity over 100U/mL. Actinomycete F4712 with high xylanase-producing (the initial enzyme activity was 349. 4U/mL) was selected for further research. The conditions including:carbon source, nitrogen source, initial pH value, rotation rate, temperature and cultivation time were investigated by single-factor experiment. Box-Behnken was utilized to the response surface analysis to determine the conditions further, which were insoluble corncob xylan 2. 8%, a combination of beef peptone 1. 0% and yeast extract 0. 5%, pH 6. 2, 130r/min, 45℃ and 6 days. The xylanase activity was 693. 4U/mL under the optimal conditions, which was improved by 98. 5% compared to the original activity.