蛹虫草液体发酵培养基的优化

采用统计学方法对1株蛹虫草Cordyceps militaris DY-1菌株进行液体发酵配方优化,以期得到适合蛹虫草生长的最佳培养基配方。以菌丝体干质量浓度为指标,首先采用单次单因子方法筛选出培养基中的最优碳源、氮源及无机盐和正交试验方法得出最佳的碳氮比(C/N);然后采用Plackett-Burman(BP)设计筛选出影响菌丝体干质量浓度的关键因素,通过中心组合和响应面法确定关键因素的最佳浓度,从而得到出菌株DY-1的液体发酵最佳培养基配方为:葡萄糖16.40 g·L-1,酵母浸膏粉5.00 g·L-1,硝酸钾1.00 g·L-1,硫酸镁0.20 g·L-1,磷酸二氢钾1.80 g·L-1,硫酸亚铁0.02 g·L-1。经验证,菌丝体干质量浓度为32.11 g·L-1,与模型的预测值基本一致。运用最佳培养基配方进行液体发酵,菌丝体干质量浓度较基础培养基提高了4.12倍。

Optimization of a liquid fermentation medium for Cordyceps militaris

To obtain the optimal medium for growth of Cordyceps militaris DY-1, statistical designs were utilized on the fermentation medium. The dry weight of mycelium was measured analytically. First, the carbon source, nitrogen source, and inorganic salts were screened one factor at a time, and the carbon: nitrogen ratio was optimized through orthogonal testing. Then, the Plackett-Burman design was used to screen the critical factors of mycelium production. Last, a central composite design and response surface methodology were utilized to determine the optimal concentrations of the critical factors. After, the optimal medium was used in inoculation experiments to verify the predicted values. Results demonstrated that the optimal media was composed of the following factors: maltose, 16.40 g·L^－1; yeast extract powder, 5.00 g·L^－1; KNO₃, 1.00 g·L^－1; MgSO₄, 0.20 g·L^－1; KH₂PO₄, 1.80 g·L^－1; and FeSO₄, 0.02 g·L^－1. The practical corresponding response of 32.11 g·L^－1 was closer to the predicted response of 32.22 g·L^－1. Using the optimum medium, the dry weight of the mycelium active substances was effectively enhanced 4.12 times compared with the initial level. The present study laid the foundation for the further research and application of Cordyceps militaris DY-1.［Ch, 3 fig. 9 tab. 28 ref.］