Abstract: In order to explore the optimal preparation method of liquid seed and fermentation conditions for mycelial biomass and cordycepin production in submerged cultivation of Cordyceps militaris (BCEC07), effect of liquid seed on mycelial growth and cordycepin production by inoculating different concentrations of spores in seed culture was investigated. Single factor tests were used to investigate the effects of medium compositions on mycelial growth and cordycepin production in liquid fermentation of C. militaris. Among these factors, sucrose, peptone, MgSO4, K2HPO4 and NAA were the most suitable carbon, nitrogen and mineral sources as well as growth factors, respectively. Through orthogonal tests and the analysis of variance, the optimal liquid media was composed of 30 g/L sucrose, 25 g/L peptone, 0.5 g/L MgSO4·7H2O, 1.5 g/L KH2PO4 and 4.0 mg/L NAA for mycelial growth and 30 g/L sucrose, 25 g/L peptone, 0.5 g/L MgSO4·7H2O, 1.5 g/L KH2PO4 and 3.0 mg/L NAA for cordycepin production, respectively. This optimal liquid medium culture resulted in the yield of cordycepin up to 645.12 mg/L and the yield of mycelial biomass up to 31.60 g/L in 500 mL shake-flask culture, which revealed the enhancement by 0.316 fold and 0.43 fold compared with the basal medium.

Key words: Cordyceps militaris, submerged culture, cordycepin, mycelial growth, liquid seed, optimization