产高活性木聚糖酶放线菌的筛选及其产酶条件的优化

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

本研究采用平板透明圈法自土样中筛选出产木聚糖酶放线菌52株,其中酶活100U/mL以上的有12株。对其中产木聚糖酶酶活较高且产酶稳定的菌株F4712(初始酶活349.4U/mL)进行了液体发酵条件优化。实验首先对培养基成分包括碳源(种类及添加量)、氮源(种类及添加量)及发酵条件:温度、发酵初始pH、摇床转速以及发酵时间等因素进行了考察。通过Box-Behnken响应面分析对发酵产酶条件做进一步优化,确定了摇瓶发酵的最优条件。结果表明,最佳发酵条件为玉米芯水不溶性木聚糖(2.8%),酵母浸膏(0.5%)及蛋白胨(1.0%)、45℃、pH6.2、130r/min以及6d。在此条件下酶活达693.4U/mL(较优化前提高了98.5%)。

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.