Optimization of culture conditions for biosynthesis of lipopeptide by Bacillus subtilis with starch

Optimization of culture conditions for lipopeptide production of lipopeptide by Bacillus subtilis NEL-01 was carried out in shaker flask batch fermentations using composite central design of response surface methodology (RSM). A five-level three-factor central composite design was employed to determine the maximum lipopeptide production at optimum levels for culture temperature, initial pH and culture cycle. Culture temperature and culture cycle showed the significant linear main effects, while pH had no significant linear effect. The production was also significantly affected by quadratic effect of culture temperature and initial pH. Optimum fermentation parameters were predicted at temperature, initial pH, and culture cycle of 34.81 degrees C, 7.33g/l, 49.26 h, respectively. The prediction lipopeptide yield was 1879.56 mg/l. The subsequent experiments confirmed the prediction.