Purification, Characterization, Mode of Action, and Application of Jileicin, a Novel Antimicrobial from <i>Paenibacillus jilinensis</i> YPG26

Abstract

Antimicrobial compounds from the commensal gut microbiota have gained much attention due to their multifunctionality in maintaining good health in the host and killing multidrug-resistant bacteria. Our previous study showed that <i>Paenibacillus jilinensis</i> YPG26 isolated from chicken intestine can antagonize multiple pathogens. Herein, we characterized a bacteriocin-like inhibitory substance, jileicin, purified from <i>P. jilinensis</i> YPG26. Mass spectrometry analysis revealed that jileicin was a protein consisting of 211 amino acids, which showed 88.98% identity to the SIMPL domain-containing protein. The jileicin showed a relatively broad-spectrum antibacterial ability, especially against enterococci. Additionally, the jileicin exhibited good stability after various treatments, no detectable resistance, no significant cytotoxicity, and very low levels of hemolytic activity. The mode of action against <i>Enterococcus faecium</i> demonstrated that jileicin could destroy cell membrane integrity, increase cell membrane permeability, and eventually lead to cell death. Furthermore, jileicin was efficient in controlling the growth of <i>E. faecium</i> in milk. In conclusion, jileicin, as a newly identified antibacterial agent, is expected to be a promising candidate for application in the food, pharmaceutical, and biomedical industries.