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Medium optimization for exopolysaccharide production in liquid culture of endophytic fungus Berkleasmium sp. Dzf12.

Li P, Xu L, Mou Y, Shan T, Mao Z, Lu S, Peng Y, Zhou L - Int J Mol Sci (2012)

Bottom Line: 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.The results provide the support data for EPS production in large scale and also speed up the application of Berkleasmium sp.Dzf12.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Pathology, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China; E-Mails: lipq110@163.com (P.L.); lbaf2006@163.com (L.X.); muyan01987@163.com (Y.M.); shan5400388@163.com (T.S.); maoziling2011@163.com (Z.M.); shiqionglu@126.com (S.L.); pengyl@cau.edu.cn (Y.P.) ; Department of Forestry Pathology, College of Forestry, Northwest A & F University, Yangling 712100, China.

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.

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Related in: MedlinePlus

The 3D-response surface and 2D-contour plots of EPS yield (g/L) versus the tested variables (g/L): glucose and peptone (A,B); glucose and MgSO4·7H2O (C,D); peptone and MgSO4·7H2O (E,F).
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3472754&req=5

f2-ijms-13-11411: The 3D-response surface and 2D-contour plots of EPS yield (g/L) versus the tested variables (g/L): glucose and peptone (A,B); glucose and MgSO4·7H2O (C,D); peptone and MgSO4·7H2O (E,F).

Mentions: The three-dimensional (3D) response surface and two-dimensional (2D) contour plots are the graphical representations of the quadratic polynomial regression equation [48]. They provide a method to visualize the relationship between the responses and the experimental levels of each variable, and the interactions between any two tested variables from the circular or elliptical nature of contour [49]. A circular contour plot indicates that the interactions between the corresponding variables are negligible. An elliptical nature of the contour plots indicates that the interactions between the corresponding variables are significant [50]. In the present study, the 3D response surfaces and 2D contour plots are presented in Figure 2, which were generated by employing the software of Design-Expert. Analyses of the 3D response surfaces and their corresponding 2D contour plots allowed us to conveniently investigate the interactions between any two variables, and locate the optimum ranges of the variables efficiently such that the response was maximized. The maximum predicted response was indicated by the surface confined in the smallest ellipse in the contour diagram.


Medium optimization for exopolysaccharide production in liquid culture of endophytic fungus Berkleasmium sp. Dzf12.

Li P, Xu L, Mou Y, Shan T, Mao Z, Lu S, Peng Y, Zhou L - Int J Mol Sci (2012)

The 3D-response surface and 2D-contour plots of EPS yield (g/L) versus the tested variables (g/L): glucose and peptone (A,B); glucose and MgSO4·7H2O (C,D); peptone and MgSO4·7H2O (E,F).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3472754&req=5

f2-ijms-13-11411: The 3D-response surface and 2D-contour plots of EPS yield (g/L) versus the tested variables (g/L): glucose and peptone (A,B); glucose and MgSO4·7H2O (C,D); peptone and MgSO4·7H2O (E,F).
Mentions: The three-dimensional (3D) response surface and two-dimensional (2D) contour plots are the graphical representations of the quadratic polynomial regression equation [48]. They provide a method to visualize the relationship between the responses and the experimental levels of each variable, and the interactions between any two tested variables from the circular or elliptical nature of contour [49]. A circular contour plot indicates that the interactions between the corresponding variables are negligible. An elliptical nature of the contour plots indicates that the interactions between the corresponding variables are significant [50]. In the present study, the 3D response surfaces and 2D contour plots are presented in Figure 2, which were generated by employing the software of Design-Expert. Analyses of the 3D response surfaces and their corresponding 2D contour plots allowed us to conveniently investigate the interactions between any two variables, and locate the optimum ranges of the variables efficiently such that the response was maximized. The maximum predicted response was indicated by the surface confined in the smallest ellipse in the contour diagram.

Bottom Line: 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.The results provide the support data for EPS production in large scale and also speed up the application of Berkleasmium sp.Dzf12.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Pathology, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China; E-Mails: lipq110@163.com (P.L.); lbaf2006@163.com (L.X.); muyan01987@163.com (Y.M.); shan5400388@163.com (T.S.); maoziling2011@163.com (Z.M.); shiqionglu@126.com (S.L.); pengyl@cau.edu.cn (Y.P.) ; Department of Forestry Pathology, College of Forestry, Northwest A & F University, Yangling 712100, China.

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.

Show MeSH
Related in: MedlinePlus