Medium optimization for palmarumycin C13 production in liquid culture of endophytic fungus Berkleasmium sp. Dzf12 using response surface methodology

Abstract

Background: Berkleasmium sp. Dzf12, an endophytic fungus from Dioscorea zingiberensis , was a high producer of palmarumycin C 13 with various bioactivities. In the present study, the experimental designs based on statistics were employed to evaluate and optimize the medium for palmarumycin C 13 production in mycelia liquid culture of Berkleasmium sp. Dzf12. Results: Among various carbon and nitrogen sources, glucose, peptone and yeast extract were found to be the most favourable for palmarumycin C 13 production based on the one-factor-at-a-time experiments. After Plackett-Burman test on the medium, glucose, peptone and yeast extract were further verified to be the most significant factors to stimulate palmarumycin C 13 accumulation. These three factors ( i.e ., glucose, peptone and yeast extract) were then optimized through the experiments of central composite design (CCD) and analysis of response surface methodology (RSM). The optimized medium compositions for palmarumycin C 13 production were determined as 42.5 g/l of glucose, 6.5 g/l of peptone, 11.0 g/l of yeast extract, 1.0 g/l of KH 2 PO 4 , 0.5 g/l of MgSO 4 x 7H 2 O, 0.05 g/l of FeSO 4 x 7H 2 O, and pH 6.5. Under the optimal culture conditions, the maximum palmarumycin C 13 yield of Berkleasmium sp. Dzf12 was increased to 318.63 mg/l, which was about 2.5-fold in comparison with that (130.44 mg/l) in the basal medium. Conclusions: The results indicate that the optimum production of palmarumycin C 13 in Berkleasmium sp. Dzf12 liquid culture can be achieved by addition of glucose, peptone and yeast extract with their appropriate concentrations in the modified Sabouraud medium.