Statistical optimization of cultivation conditions for exopolysacchride production and mycelia growth by Stropharia rugosoannulata

Response surface methodology (RSM) was successfully applied to investigate the effect of cultivation temperature, time and volume of media on mycelia growth, in the light of exopolysaccharide content (EPC) and dry cell weight (DCW), by the fungus Stropharia rugosoannulata in submerged culture. The three significant factors influencing EPC and DCW were based on the results of a previous Plackett–Burman (PB) design. Results showed that the maximum predicted values of EPC and DCW reached 1,498.17 mg l −1 and 9.89 g l −1 , while the optimized conditions of cultivation temperature, time and volume of media for EPC and DCW were 28.35°C, 6.67 days, and 110.29 ml, and 28.23°C, 6.58 days, and 109.17 ml, respectively. When the above conditions were 28.29°C, 6.63 days, and 109.69 ml, the simultaneously maximal yield of exopolysaccharide and mycelia biomass were 1,498.08 mg l −1 and 9.88 g l −1 , respectively. These predicted values were also verified by validation experiments.