Optimization of Fermentation Medium for Epothilones Production with Sequential Statistical Approach

A sequential statistical approach was applied to optimizing the fermentation medium of epothilones（Epos） production by means of a mutant which was obtained by treating polyangium cellulosum ATCC 15384 with nitrite and ultraviolet. The effects of different carbon sources and nitrogen sources on the fermentation medium were tested, and the suitable ones were selected. Then a uniform design was employed to design the experiments. A linear model was developed for identifying the significant components in fermentation medium, while a third degree polynomial model was used for studying the relationship between the concentration of the components in fermentation medium and the yield of Epos（YEPs）. A pattern search method was used for searching the optimum fermentation medium in the test space, which was as follows（g/L）： potassium nitrate 8.00, soybean peptone 17.60, potassium hydrogen phos- phate 1.00, beef extraction 6.46, yeast extraction 1.00, calcium chloride 0.25, sodium chloride 1.00 and ferric chloride 0.02. The optimum fermentation medium was expected to result in a yield of Epos（YEPs） of 2.48 mg/L. The validation experiments with the optimum medium were performed in triplicate and the average yield of Epos was 2.45 mg/L which was 7.78 times higher than that of Epos prepared without optimization.

Study on the Optimization of Bio-emulsifier Production by Geobacillus sp.XS2 Based on Response Surface Methodology

[Objective] The aim was to study the optimization of bio-emulsifier production by Geobacillus sp.XS2 based on response surface methodology.[Method] Firstly,single factor experiment was conducted to find out the main medium components influencing bio-emulsifier production by Geobacillus sp.XS2,and then response surface model was established by using response surface methodology and Design-Expert 7.0,so as to optimize the fermentation medium for bio-emulsifier production by Geobacillus sp.XS2.[Result] Glucose,KH2PO4 and K2HPO4 were the main impact factors of bio-emulsifier production by Geobacillus sp.XS2,and its optimal fermentation medium was composed of 68 g/L glucose,2 g/L NaNO3,5.03 g/L KH2PO4,1.36 g/L K2HPO4,0.2 g/L MgSO4·7H2O,0.02 g/L FeSO4·7H2O,0.01 g/L CaCl2·2H2O and 2 ml microelement solution.Under the optimal conditions,the measured emulsifying activity of bio-emulsifier (67.0%) was close to predictive value (66.7%) and increased by 27% compared with previous value before optimization.[Conclusion] Response surface methodology was applicable to the optimization of fermentation medium of bio-emulsifier production by Geobacillus sp.XS2,and its optimal result was consistent with actual result.