Discovery of a Novel Antimicrobial Lipopeptide, Brevibacillin V, from Brevibacillus laterosporus fmb70 and Its Application on the Preservation of Skim Milk

Increasing cases of infections by foodborne pathogenic bacteria resulted in a great demand to find safe and novel antimicrobial compounds that can be used in the food industry. The isolation and application of antimicrobial peptides including lipopeptides has been increasing tremendously in the past years. In this study, a new bacterial strain called Brevibacillus laterosporus fmb70 (fmb70) was isolated and exhibited strong antimicrobial activities against Gram-positive, Gram-negative bacteria, and fungi. Two major antimicrobial components produced by fmb70 were respectively identified as lipopeptide: brevibacillin V (MW: 1570.12 Da) and brevibacillin (MW: 1583.75 Da), of which brevibacillin V was a new compound. Both of them consisted of 13 amino acids and C₆ fatty acyl (FA) chain. Brevibacillin V and brevibacillin showed significant antimicrobial activities against most foodborne pathogenic bacteria and phytopathogenic fungi. They stayed activity at 100 °C and remained 50% of their antimicrobial activities at pH 3 for 22 h. Hemolytic activities of them were lower than 8%. They effectively eliminated the S. aureus GIM 1.142 and L. monocytogenes ATCC 21633 in skim milk. In conclusion, the Brevibacillus laterosporus fmb70 and its major antimicrobial components has remarkable potentials in the food industry.