Structural characterization and temperature-dependent production of C-17-fengycin B derived from Bacillus amyloliquefaciens subsp plantarum BC32-1

Cyclic lipopeptides were produced by Bacillus amyloliquefaciens subsp. plantarum strain BC32-1 that was isolated from yellow loess soil in the Jeonnam province of South Korea. Several lipopeptides were isolated from the bacteria using organic solvent extraction and reverse-phase high-performance liquid chromatography (RP-HPLC). Purified iturin-, surfactin-, and fengycin-type lipopeptides were identified using liquid chromatographymass spectrometry (LC-MS) analysis. Among the lipopeptides, C-17-fengycin B showed strong antifungal activity against the phytopathogenic fungus, Fusarium oxysporum f. sp. radicis-lycopersici, and then the fengycin was further characterized by UV, Fourier transform-infrared spectroscopy (FT-IR), and LC-MS/MS analyses. C-17-fengycin B was highly produced at quantities of up to 15 A mu g/mL at 37A degrees C, whereas little amount of the fengycin was produced at 25A degrees C. Purified C-17-fengycin B inhibited mycelial growth of F. oxysporum with a minimal inhibitory concentration of 50 A mu g/mL. This study suggests that C-17-fengycin B is a major antifungal component produced by the BC32-1 strain that could be used as an environmentally friendly agent to control the phytopathogenic F. oxysporum.