The efficient synthesis strategy of bacillomycin D in Bacillus amyloliquefaciens fmbJ

The cyclic lipopeptide bacillomycin D exhibits potent antifungal activity against a wide range of fungi, particularly filamentous fungi, thereby exhibiting significant potential for application in food preservation. However, the limited yield obtained from wild strains hinders the practical application of bacillomycin D. In this study, we used different strategies to modify the original strain Bacillus amyloliquefaciens fmbJ, including promoter replacement, competitive synthetic gene knockout, and overexpression of the lipopeptide transporter gene. Subsequently, we analyzed changes in the production and expression of bacillomycin D genes in the engineered strain. The results demonstrated that P_bacA exhibits the highest promoter activity, leading to a significant increase (2.05-fold) in bacillomycin D production compared with control group. Additionally, deletion of the epsA-O gene cluster also significantly enhances the synthesis of bacillomycin D. However, when amyloid gene cluster tasA-sipW-yqxM was deleted,bacillomycin D accumulation time was shortened, resulting in no significant increase in bacillomycin D production. In addition, lipopeptide transporters SwrC, KrsE and YcxA did not promote bacillomycin D production. Finally, by replacing the promoter P_bacA, we successfully disrupted the epsA-O gene cluster, and bacillomycin D production increased by 2.55 times compared to the initial bacillomycin D strain. In conclusion, this study indicated that genetic engineering of regulatory genes was an effective strategy to improve the yields of bacillomycin D and provided promising strains for industrial production of bacillomycin D.