Optimization of Lipopeptide Production Medium by Solid-State Fermentation of Bacillus subtilis and Preliminary Identification of Lipopeptide

In order to improve the yield of antimicrobial lipopeptides, soybean meal was used as the major substrate for solid-state fermentation to produce antimicrobial lipopeptide in this study. The antimicrobial substances were preliminarily identified by a high performance liquid chromatography. Subsequently, the optimization was performed by Plackett-Burman design and response surface methodology. Results showed that:The main antimicrobial lipopeptides produced were iturin (m/z 1043.6, 1057.5, 1070.2, 1084.0), fengcin (m/z 717.4, 734.7).Plackett-Burman design method was further adopted to screen the significant factors affecting fermentation. And the addition amount of MgSO₄, K₂HPO₄, and FeSO₄ were identified as the three significant factors (p<0.05) affecting the fermentation. Under the optimized conditions of MgSO₄ 0.39%, K₂HPO₄ 1.7% and FeSO₄ 0.13%, the inhibitory rate of antimicrobial lipopeptide reached 75.62%±0.36%, which laid the foundation for the industrial production of antimicrobial lipopeptide.