Optimization of Submerged Culture Conditions for Mycelial Growth and Cordycepin Production of Medicinal Fugus Cordyceps Militaris

摘要

This study was aimed to optimize the conditions of submerged culture for mycelial growth and cordycepin production of C.miiitaris by one-factor-at-a-time and orthogonal layout methods. The one-factor-at-a-time method was used to investigate the effects of medium components and environmental factors on mycelial growth and cordycepin production. The optimal initial pH value and temperature for mycelial growth were 6.0 and 20°C, while those for cordycepin production were 5.0 and 26° C, respectively. Among the medium components, sucrose, peptone, MgSO4, K2HPO4, NAA were the most suitable carbon, nitrogen, mineral sources and growth factor. Subsequently, the concentration of these medium components was optimized using the orthogonal layout method. The effects of media composition on the mycelial growth of C. militaris were orderly sucrose > peptone > MgSO4· 7H2O > K2HPO4 > NAA, and those on cordycepin production were orderly peptone > K2HPO4 > NAA > MgSO4-7H2O > sucrose. The optimal concentration of the components for mycelial growth were 40g/I sucrose, 25g/I peptone, 0.5g/l MgSO4·7H2O, 1.5g/I K2HPO4,2.0mg/l NAA, and those for cordycepin production were 40 g/l sucrose, 15 g/1 peptone, 0.5 g/l MgSO4·7H20,0.5 g/l K2HPO4,4.0mg/l NAA. This optimization strategy in shake flask culture resulted in a mycelial yield of 22.97 g/l, and cordycepin production in culture broth and in cells were 961.21 mg/1 and 12.87 mg/g respectively. The results obtained in this work will have a potential impact on the industrial scale production of cordycepin by submerged culture.