Optimization of liquid fermentation medium for cordycepin production by Cordyceps militaris with response surface methodology

The response surface methodology(RSM) was applied to optimizing the liquid fermentation medium components of Cordyceps militaris—glucose,yeast extract,KH2PO4 and MgSO4.The multivariate quadratic regression equation was used to imitate the functional relationship between the four kinds of factors and cordycepin production.By the response surface regression analysis,the optimal concentration of the four factors in the medium were determined as follows: glucose is 30.16 g/L,yeast extract is 10.00 g/L,KH2PO4 is 2.040 g/L,MgSO4 is 1.460 g/L.Under this condition,the cordycepin production predicted by the response surface model was 63.69 mg/L.The validation test result under the optimal culture medium condition was 64.15 mg/L.That is consistent with the predictive value,which indicates that the model can be used to predict the yield of cordycepin.