翘鳞伞胞外多糖液体培养条件响应曲面法优化研究

采用Plaekett—Bummn设计法对影响翘鳞伞（Pholiotasquarrosa）AS5．245深层发酵产胞外多糖的内在和外在因素进行了筛选，所选取的6个相关因素为：初始pH、培养温度、发酵时间、装液量、接种量、摇床转速。在此基础上，再采用响应曲面法（Response Surface Methodology，RSM）对影响翘鳞伞发酵胞外多糖的关键影响因素培养温度、发酵时间和接种量的最佳水平范围作了进一步的研究与探讨，通过对二次多项回归方程求解得知，在上述自变量分别为培养温度26．67％、发酵时间7．44d和接种量9．60％时，胞外多糖产量的最大预测值为910．22μg／ml。

Research on optimization of cultivation conditions for extracellular polysaccharide by Pholiota squarrosa using response surface methodology

Our previous work has indicated that the cultivation conditions for extracellular polysaccharide by Pholiota squarrosa are strongly affected by many internal and external factors. In this study, we have used an effective two-phase statistical approach to enhance extracellular polysaccharide production. In the first phase, Plackett-Burman design was undertaken to evaluate the ef- fects of 6 factors including initial pH, culture temperature, fermentation time, volume of medium, amount of inoculum and rotation speed. By regression analysis,culture temperature,time and amount of inoculum were found to be important to cultivation condi- tions for extracellular polysaccharide by Pholiota squarrosa. In the second phase of the optimization process, a response surface methodology （RSM） was used to optimize the above critical factors and to find out the optimal concentration levels and the rela- tionships between these factors. Based on the results of the first phase, a three-level three-factor （culture temperature, fermenta- tion time and amount of inoculum） Box-Behnken design was adopted. By solving the quadratic regression model equation using appropriate statistic methods, the optimal concentrations for obtaining 910.22 μg/mL extracellular polysaccharide production was calculated as： culture temperature 26.67℃, fermentation time 7.44 d and amount of inoculum 9.60%.