Bacillomycin D: an iturin with antifungal activity against Aspergillus flavus

Aims: In a search for an antifungal peptide with a high activity against As pergillus flavus, Bacillus subtilis AU195 was selected from a collection of isolates with antagonistic activity against A. flavus. Methods and Results: To identify the antifungal peptides, a protein purific ation scheme was developed based on the detection of the antifungal activit y in purified fractions against A. flavus. Two Lipopeptides were purified w ith anion exchange and gel filtration chromatography, Their masses were det ermined to be 1045 and 1059 m/z with mass spectrometry, and their peptide m oiety was identical to bacillomycin D. Conclusions: AU195 synthesized a mixture of two antifungal bacillomycin D a nalogues with masses of 1045 and 1059, the 14 mass unit difference represen ting the difference between a C15 and a C16 lipid chain. Significance and Impact of the Study: Both bacillomycin D analogues were ac tive at the same concentration against A. flavus, but the different lipid c hain length apparently affected the activity of the lipopeptide against oth er fungi.