title: Medium optimization for exopolysaccharide production in liquid culture of endophytic fungus Berkleasmium sp. Dzf12.
abstract: 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, KH(2)PO(4), MgSO(4)·7H(2)O and FeSO(4)·7H(2)O 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 MgSO(4)·7H(2)O 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-R(2)) as 0.9434. By solving the quadratic regression equation, the optimal concentrations of glucose, peptone and MgSO(4)·7H(2)O 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.
authors.affiliation: Department of Plant Pathology, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China.|Department of Forestry Pathology, College of Forestry, Northwest A & F University, Yangling 712100, China.
authors.forename: Peiqin
authors.initials: P
authors.lastname: Li
authors.affiliation: Department of Plant Pathology, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Xu
authors.affiliation: Department of Plant Pathology, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Mou
authors.affiliation: Department of Plant Pathology, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China.
authors.forename: Tijiang
authors.initials: T
authors.lastname: Shan
authors.affiliation: Department of Plant Pathology, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China.
authors.forename: Ziling
authors.initials: Z
authors.lastname: Mao
authors.affiliation: Department of Plant Pathology, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China.
authors.forename: Shiqiong
authors.initials: S
authors.lastname: Lu
authors.affiliation: Department of Plant Pathology, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China.
authors.forename: Youliang
authors.initials: Y
authors.lastname: Peng
authors.affiliation: Department of Plant Pathology, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China.
authors.forename: Ligang
authors.identifier: 0000-0003-4681-191X
authors.initials: L
authors.lastname: Zhou
mesh_terms: D001203:Ascomycota / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry*; D003627:Data Interpretation, Statistical; D062610:Fungal Polysaccharides / Q000096:biosynthesis*
chemical_list: D003470:Culture Media; D062610:Fungal Polysaccharides
keywords: center composite design; endophytic fungus Berkleasmium sp. Dzf12; exopolysaccharide; fractional factorial design; medium optimization; response surface methodology