Application of response surface methodology in medium optimization for spore production of Coniothyrium minitans in solid-state fermentation

Abstract

Spore production of Coniothyrium minitans was optimized by using response surface methodology (RSM), which is a powerful mathematical approach widely applied in the optimization of fermentation process. In the first step of optimization, with Plackett–Burman design, soluble starch, urea and KH2PO4 were found to be the important factors affecting C. minitans spore production significantly. In the second step, a 23 full factorial central composite design and RSM were applied to determine the optimal concentration of each significant variable. A second-order polynomial was determined by the multiple regression analysis of the experimental data. The optimum values for the critical components for the maximum were obtained as follows: soluble starch 0.643 (36.43 g. l−1), urea −0.544 (3.91 g l−1) and KH2PO4 0.049 (1.02 g l−1) with a predicted value of maximum spore production of 9.94 × 109 spores/g IDM. Under the optimal conditions, the practical spore production was 1.04 × 1010 spores/g IDM. The determination coefficient (R2) was 0.923, which ensure an adequate credibility of the model.