Optimization of medium on exopolysaccharides production in submerged culture of Cordyceps militaris

Abstract

Statistical experimental design strategy (SES) was applied to optimize the medium for the exopolysaccharides (EPS) production of Cordyceps militaris by submerged culture in shaker flask. A significant influence of the glucose and peptone on the EPS production was first evaluated by using a Plackett-Buman design. Then, steepest ascent method was employed to approach the experimental design space. Last, these factors were further optimized using central composite design (CCD) and response surface methodology (RSM). A quadratic model was found to fit the EPS production. The optimum values of the tested variables for the production of EPS were 48.67 g/L glucose, 12.56 g/L peptone, 1 g/L KH2PO4, 10 g/L yeast extract, and 0.5 g/L MgSO4·7H2O. Under optimization of culture conditions, the EPS production was enhanced from 0.78 to 1.96 g/L. In comparison with that of original culture conditions, 2.5 fold increase was obtained.