Abstract: The objective of the present study was the optimization of liquid fermentation medium for producing intracellular polysaccharide by Phellinus baumii by response surface methodology. The effects of carbon source, nitrogen source, and metal ions on mycelium biomass and intracellular polysaccharide production were explored in single factor experiments, and corn flour and wheat bran were found to be the best carbon source and nitrogen source, respectively. Based on this, the optimum levels of corn flour, wheat bran, KH2PO4 and MgSO4 were determined by Box-Benhnken design combined with response surface analysis to be 3.9%, 2.2%, 0.20% and 0.10%, respectively. The intracellular polysaccharide production in optimized medium reached 233.107 mg/L.

Key words: Phellinus baumii, liquid-state fermentation, culture medium, intracellular polysaccharide, response surface methodology