Bacillus velezensis GH1‐13 was recently isolated and showed to promote plant growth and strong antagonistic effects against phytopathogenic fungi including Gibberella moniliformis, Fusarium fujikuroi, Bipolaris oryzae, and Colletotrichum gloeosporioides. In this study, the antifungal substances produced by the GH1‐13 strain were purified by ethyl acetate solvent partitioning and solid phase extraction using Sep‐Pak C18 cartridge. The pure antifungal substances were finally purified by preparative reversed phase‐high performance liquid chromatography. We investigated the structure of the purified antifungal compounds using liquid chromatography mass spectrometry and nuclear magnetic resonance spectroscopy. These compounds were identified as surfactin‐type cyclic lipopeptides having an ELLVDLL amino acid sequence with different lengths of lipid chains. The surfactin lipopeptides effectively inhibited the growth of fungal mycelium, suggesting that the GH1‐13 strain will be a potential biocontrol agent against plant pathogenic fungi.

Pelgipeptins are cyclic lipopeptides composed of nine amino acids and a short fatty acid chain. In the present study, we report a novel pelgipeptin peptide that was isolated from Paenibacillus elgii BC34-6 and named pelgipeptin E (PGP-E). The molecular mass of PGP-E was 1072 Da as determined by liquid chromatography-mass spectrometry and the amino acid sequence was elucidated by tandem mass spectrometry. The complete molecular structure of PGP-E was characterized using 2D NMR spectroscopy. PGP-E consisted of a cyclic peptide backbone of Dab1-Val2-Dab3-Phe4-Leu5-Dab6-Val7-Leu8-Ser9 and a lipid chain (-CHCHCH). PGP-E had broad antimicrobial activity against gram-negative and -positive bacteria, including methicillin-resistant Staphylococcus aureus strains. Furthermore, the mode of action of PGP-E was investigated using calcein dye leakage and membrane depolarization assays, which suggest that PGP-E acts via a membrane-active mechanism. The hemolytic activity of PGP-E was significantly lower than that of melittin, a well-known membrane-active peptide derived from bee venom. These results suggest that PGP-E is a potential candidate in the development of new peptide antibiotics.