Bacillomycin D lipopeptides from marine Bacillus megaterium as antimicrobial and preservative agents for large yellow croaker, Larimichthys crocea

Large yellow croaker (Larimichthys crocea) has rich protein content and high economic value, but has a short shelf life. Lipopeptides extracted from marine Bacillus megaterium were applied to the preservation of large yellow croaker and effectively increased the shelf life of large yellow croaker. The results showed that the total viable count (the total number of colonies), total volatile base nitrogen, texture and other indicators in the treatment groups were better than control and the difference was significant (p < .05). Furthermore, bacillomycin D with 14 and 15 carbon atoms in beta-amino fatty acids was separated from the lipopeptides and it was used to study its inhibitory effect on Aspergillus flavus, and the minimum inhibitory concentration and minimal fungicidal concentration were 50 mu g/mL and 200 mu g/mL, respectively. Bacillomycin D significantly inhibited the spores germination, mycelial growth, and sporulation of A. flavus. The results of scanning electron microscopy and transmission electron microscopy showed that the morphology of A. flavus was changed, and cell contents was leak after treatment with bacillomycin D. Practical applications Marine B. megaterium suspension and lipopeptides extracted from the strain of marine B. megaterium were applied to the preservation of large yellow croaker, and it laid the foundation for studying more potential effects of lipopeptides. Furthermore, in this study, bacillomycin D was separated from lipopeptide and it was identified 14 and 15 carbon atoms in beta-amino fatty acids. It was well-stabilized and could later be used as preservative for large yellow croaker. The preliminary application of the preservation of large yellow croaker had proved that lipopeptides have a good development and application prospect as a new type of aquatic preservative.