Characterization of brevilaterins, multiple antimicrobial peptides simultaneously produced by Brevibacillus laterosporus S62-9, and their application in real food system

Abstract

Abstract: Multiple antimicrobial peptides (designated brevilaterin) were extracellularly produced by Brevibacillus laterosporus S62-9, five brevilaterins were purified by liquid chromatography, and characterized by MALDI-TOF/TOF MS and 2D-NMR. The results suggested that brevilaterin A-E (Mw 1568.9753, 1555.0334, 1601.0044, 1569.0189, 1583.0946\xa0Da) showed similar primary structures exhibiting small variation of three amino acid substitutions at residue 3, 5, 7. Every brevilaterin contained a fatty acid (2-hydroxy-3-methylpentanoic acid) at the N-terminus and 13 amino acids including three modified amino acids: 2-amino-2-butenoic acid, ornithine and C-terminal residue of valinol, of which brevilaterin D was a new compound. Brevilaterins showed broad antimicrobial activities against bacteria and fungi, and were resistant to heat (retained over 80% antimicrobial activity at 121\xa0°C for 20\xa0min) and pH (no significant loss at pH 2 to 12). They effectively killed Staphylococcus aureus in milk. Collectively, these findings evidenced a promising application of brevilaterins in food preservation.