Antimicrobial Peptide from Bacillus Strain K1R Exhibits Ameliorative Potential Against Vancomycin-Resistant Enterococcus Group of Organisms

Microorganisms secrete antimicrobial peptides (AMPs) which are part of the innate immune system and rapidly increase in concentration in the host upon challenge by pathogens, which they produce themselves. Kimchi, a traditional Korean food fermented by Bacillus organisms, is found to be ideal for AMP production. Our aim was to investigate the therapeutic potential of antimicrobial substances produced by Bacillus species. Peptide K1R was subjected to fermentation in a culture media containing carbon and nitrogen sources and metal ions. A protein band around 4.6 kDa was detected in tricine-SDS-PAGE and confirmed by in situ inhibitory activity of the gel. Peptide K1R was stable over a broad range of pH (6.5–9), thermo tolerant up to 60 °C and showed unaltered activity at low temperatures (0–4 °C). The complete amino acid sequence of peptide K1R was AVQGTLEDALNLSKGALNQVQKAIQNGDXLTVXGXLGTIXLAVSX. The antagonistic effect of peptide K1R against multiple drug resistant (MDR) pathogens such as Salmonella Typhimurium and Enterococcus sp. verified its potential application in treating MDR cases. The antioxidant activity of peptide K1R was also comparable to that of standard ascorbic acid.