牛肝菌摇瓶发酵条件优化研究

Optimization of Fermentation Conditions for Exopolysaccharide and Mycelium Biomass by Boletus sp. ACCC 50328

在Plackett Burman实验结果基础上 ,采用响应曲面法 (responsesurfacemethodology ,RSM )对影响牛肝菌 (Boletussp )ACCC 5 0 3 2 8发酵产糖与生长的关键工艺参数 ,发酵温度、发酵时间和装液量的最佳水平范围进行了研究和探讨。通过对胞外多糖曲面方程以及菌丝干重二次多项回归方程求解得知 ,在自变量发酵温度 ,发酵时间和装液量分别为 2 4 2 3℃、1 0 7d和 5 0 0mL时 ,牛肝菌ACCC 5 0 3 2 8菌株发酵胞外多糖的最大预测值为 1 0 5 3 99μg/mL发酵醪 ;在 2 6 77℃、1 0 9d和 64 90mL时 ,该菌干菌丝浓度可达 4 2 2mg/mL发酵醪。欲同时获得最大量的胞外多糖和菌丝浓度 ,则发酵温度 ,发酵时间和装液量须为 2 6 2 3℃、1 0 5d和 5 8 70mL ,在此条件下 ,每毫升发酵醪中的胞外多糖含量和菌丝浓度分别为 992 2 6μg与 4 1 6mg。上述预测值不仅被统计学方法所验证 。

Response surface methodology (RSM) based on a three level three factor Box Behnken design of experiments was used to optimize the exopolysaccharide content (EPC) by using submerged fermentation of Boletus sp ACCC 50328, and the mycelium biomass seeparately, in terms of dry cell weight (DCW) The critical factors selected were temperature, time of fermentation and broth content based on the results of our previous Plackett Burman design The objectives of the present work were to locate optimum level of these process parameters, and to find out interactions among that for enhancement of exopolysaccharide yield By solving the regression equation and analyzing the response surface contour plots, the optimal process conditions were determined: 7 d fermentation time; temperature of 24 23℃; and broth content of 50 0 ?mL, EPC obtained from Plackett Burman design was increased from 610.78 to 1053 99 μg per milliliter of fermentation liquor While fermentation time, temperature and broth content were 10 9 d, 26 77℃ and 64 90?mL, DCW was increased from 3 42 to 4 22 mg/mL In order to obtain the maximum yield of EPC and DCW, conditions would be located at 10 5 d, 26 23℃, and 58 70?mL. Under this conditions, the maximum predicted yield of EPC and DCW were found to be 992 26 μg/mL and 4 16 mg/mL, respectively These predicted values were also verified by validation experiment