响应面法优化芽孢杆菌25-2产纤维素酶发酵条件

Optimization of Fermentation Conditions of Bacillus 25-2 for Cellulase Production by Response Surface Methodology

为了提高芽孢杆菌25-2产纤维素酶的能力,利用响应面法对其发酵条件进行优化。通过二水平设计的Plackett-Burman实验分析6种因素对芽孢杆菌产纤维素酶活力的影响,筛选出发酵时间(X1)、发酵温度(X2)、初始pH值(X3)3个影响酶活的显著性因素。在此基础上采用最陡爬坡实验逼近最大响应区域,并结合中心组合实验以及响应面分析对影响纤维素酶产量的关键因素的最佳水平范围作进一步研究和讨论。建立了以纤维素酶活为响应值的二次回归方程模型,从中分析得到最优发酵条件:发酵时间21.7 h,发酵温度46℃,初始pH值4.8。在以上优化条件下发酵,供试菌株的纤维素酶酶活达到28.626 U/mL,较优化前提高了1.748倍,其实验值与预测值基本相符。

In order to enhance cellulase-producing capacity of Bacillus 25-2, response surface method was applied to optimize its fermentation conditions. Firstly, two level factorial design of Plackett-Burman was used to evaluate the effects of six related factors on cellulase activity. Three factors including fermenting time（X1）, fermentation temperature（X2） and initial pH value（X3）, as the significant factors influencing cellulase activi- ty, were screened out, Then the path of steepest ascent experiments were adopted to approach the optimal region of fermentation conditions, Box-Behnken design and response surface methodology （RSM） analysis were applied to analyze the relationships between these factors and to find out the optimal values of the critical factors. Then second-order regression equation model was further establish and the optimal conditions of the three factors were assessed by RSA as follows： 21.7 h of fermenting time, fermentation temperature was at 46℃, and initial pH value was 4.8. Under the above conditions, the activity of cellulase increased nearly 1.704 times than before to 27.907 U/mL and the experimental values agreed with the predicted values.