Statistical optimization of the fermentation medium for L-lactic acid fermentation

The fermentation medium for L-lactic acid fermentation was optimized by Plackett-Burman design,steepest climbing experimental design and response surface methodology.Plackett-Burman experimental design study of 8 factors in the medium fractions,the liquid of potato saccharification,yeast extract and manganese sulfate selected three significant factors,choose these three factors as the main subjects for further optimization work.Steepest ascent experiment factors determined the center of response surface experimental.Central composite design and response surface methodology were employed to investigate the interaction of the variables and to ascertain the optimal values of the factors,which finally led to the maximum lactic acid production.The theoretical optimal conditions were: the liquid of potato saccharification 110.7 g/L,yeast extract 14.98 g/L,manganese sulfate 0.016 g/L,the maximum lactic acid yield was 94.09 g/L.To verify the optimal experimental conditions,an average of three experiments 93.2 g/L,and the error value was 0.9% between the predicted.Compared with the former,lactic acid production increased 11.2%,L-lactic acid purity was 94.8%.