Chemical Investigation of Active Lipopeptides Produced by Bacillus subtillis natto and the Application in Animal Feed

Surfactin is a highly effective surfactant produced by bacteria, and commonly used as an antibiotic or probiotic. Due to its low UV absorption, it is not easy to detect this type of lipopeptides by HPLC directly, so we use thin layer chromatography combined with ninhyrin reaction, and various column chromatography to identify and purify surfactins from Bacillus subtilis. Secondly, the antibacterial effect of lipopeptide was examined, with the purpose to evaluate the potential to replace antibiotics in feed. Third, since Aspergillusniger has a strong enzyme production system, such as amylase and cellulose, the co - cultivation of Aspergillusniger and Bacillus subtilis on feed could increase the available nutrition. Both microorganisms are safe and are allowed to be used in feed fermentation, but the accumulation of secondary metabolites will be different from the solo fermentation, especially the formation of sufactins. So, the co - cultivation of Aspergillusniger and Bacillus subtilis on animal feed was studied.