Investigating the Bacteriostatic Activity and Bactericidal Mechanism of Bacteriocin-like YY-1 Produced by Latilactobacillus sakei W-1 Against Escherichia coli

Research has demonstrated that the presence of synthetic preservatives tends to disrupt the balance of the gut microbiota, thereby posing a significant threat to food safety and human health. The present study investigates the antibacterial activity of a novel bacteriocin-like produced by Latilactobacillus sakei (L. sakei) against Escherichia coli (E. coli), as well as its mechanism of action. This study aims to validate the significant antibacterial effect of bacteriocin-like YY-1 produced by L. sakei W-1 through dialysis combined with Tricine-SDS-PAGE analysis, and to determine its molecular weight. The results of the study indicate that the molecular weight of the bacteriocin-like is less than 2.7 kDa. Moreover, this bacteriocin-like YY-1 exhibits broad-spectrum antimicrobial properties, demonstrating antibacterial activity against E. coli, S. Typhimurium, A. baumannii, P. mirabilis, S. aureus, L. monocytogenes. Furthermore, bacteriocin-like YY-1 exhibits optimal antibacterial activity at a pH of 4.0, with its activity gradually diminishing as pH increases. It is completely inactivated by trypsin treatment, while papain and proteinase K treatments significantly reduce its antibacterial activity. Additionally, this bacteriocin-like YY-1 has been demonstrated to inhibit the growth of E. coli and disrupt its normal development. The Viable/Necrotic Cell Stain and SEM observations confirmed that the bacteriocin-like compound induces cell death by forming distinct pores through the disruption of the cell membrane’s structural integrity. In summary, YY-1—a bacteriocin-like substance characterised by its low molecular weight (<2.7 kDa), broad-spectrum activity, and pore-forming mechanism—is a highly promising natural alternative to synthetic preservatives, capable of mitigating the damage caused by chemical additives to the gut microbiota.