Optimization of fermentation medium for chlortetracycline production by response surface methodology

Objective To optimize the fermentation medium of Streptomyces aureofacien for chlortetracycline production by response surface methodology.Methods First,the Plackett-Burman design was applied to screen out the major factors influencing the production of chlortetracycline.Subsequently,the steepest ascent experiments were performed to approach the optimal region of the medium composition.Finally the optimal concentrations of the major factors were determined and the optimized fermentation medium was obtained through response surface methodology of Box-Behnken design.Results Corn starch concentration,yeast powder concentration and(NH4)2SO4 concentration were found to be the major factors affecting chlortetracycline production significantly.And their optimal levels were observed when 125.10 g · L-1 of corn starch,4.03 g · L-1of yeast powder and 4.87 g · L-1of(NH4)2SO4 were used.Under the optimized medium,the yield of chlortetracycline was 22.813 g · L-1,which was close to the predictive value.The production was increased by 17% compared with that under the original medium,which was 19.476 g · L-1.Conclusions The experimental design and analysis of response surface methodology can be used to optimize effectively the fermentation medium for chlortetracycline production.