Medium Optimization for Exopolysaccharide Production in Liquid Culture of Endophytic Fungus Berkleasmium sp. Dzf12

International Journal of Molecular Sciences

Peiqin Li¹  Liang Xu¹  Yan Mou¹  Tijiang Shan¹  Ziling Mao¹  Shiqiong Lu¹  Youliang Peng¹ 

[1] Department of Plant Pathology, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China; E-Mails:

关键词: medium optimization;    endophytic fungus Berkleasmium sp. Dzf12;    exopolysaccharide;    fractional factorial design;    center composite design;    response surface methodology;   

DOI  :  10.3390/ijms130911411

来源: mdpi

【 摘 要 】

Berkleasmium sp. Dzf12, an endophytic fungus from Dioscorea zingiberensis, is a high producer of spirobisnaphthalenes with various bioactivities. The exopolysaccharide (EPS) produced by this fungus also shows excellent antioxidant activity. In this study, the experimental designs based on statistics were employed to evaluate and optimize the medium for EPS production in liquid culture of Berkleasmium sp. Dzf12. For increasing EPS yield, the concentrations of glucose, peptone, KH₂PO₄, MgSO₄·7H₂O and FeSO₄·7H₂O in medium were optimized using response surface methodology (RSM). Both the fractional factorial design (FFD) and central composite design (CCD) were applied to optimize the main factors which significantly affected EPS production. The concentrations of glucose, peptone and MgSO₄·7H₂O were found to be the main effective factors for EPS production by FFD experimental analysis. Based on the further CCD optimization and RSM analysis, a quadratic polynomial regression equation was derived from the EPS yield and three variables. Statistical analysis showed the polynomial regression model was in good agreement with the experimental results with the determination coefficient (adj-R²) as 0.9434. By solving the quadratic regression equation, the optimal concentrations of glucose, peptone and MgSO₄·7H₂O for EPS production were determined as 63.80, 20.76 and 2.74 g/L, respectively. Under the optimum conditions, the predicted EPS yield reached the maximum (13.22 g/L). Verification experiment confirmed the validity with the actual EPS yield as 13.97 g/L, which was 6.29-fold in comparison with that (2.22 g/L) in the original basal medium. The results provide the support data for EPS production in large scale and also speed up the application of Berkleasmium sp. Dzf12.

【 授权许可】

CC BY   
© 2012 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland.