Enterocin from Enterococcus hirae as a Natural Antimicrobial: Characterization and Effective against Escherichia coli and Staphylococcus aureus

This study analyzes the effectiveness of Enterocin produced by Enterococcus hirae against Escherichia coli and Staphylococcus aureus. Enterocin production was carried out by culturing E. hirae in MRS Broth at 37°C for 24 hours under anaerobic conditions. SDS-PAGE analysis revealed that the enterocin had a molecular weight ranging from 6 to 8 kDa, consistent with Class II bacteriocins. FTIR spectroscopy confirmed the presence of amide functional groups, indicating the proteinaceous nature of the compound. Morphological damage in bacterial cells was visualized using FE-SEM, where treated cells exhibited disrupted membranes and structural disintegration. Subsequent EDX analysis supported ion leakage and cellular damage, while the minimum bactericidal concentration (MBC) assay demonstrated the potent bactericidal effect of the enterocin. These findings indicate that enterocin from E. hirae exhibits significant bactericidal activity through membrane disruption and holds potential as a novel antimicrobial agent against both Gram-positive and Gram-negative bacteria.

本研究分析了海氏肠球菌（Enterococcus hirae）产生的肠球菌素（Enterocin）对大肠杆菌（Escherichia coli）与金黄色葡萄球菌（Staphylococcus aureus）的抑菌效果。实验通过将海氏肠球菌接种于MRS肉汤（MRS Broth）中，于37℃厌氧条件下培养24小时以制备肠球菌素。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）分析结果显示，该肠球菌素的分子量介于6至8 kDa之间，与II类细菌素（Class II bacteriocins）的特征相符。傅里叶变换红外光谱（FTIR）检测证实样品中存在酰胺官能团，表明该化合物为蛋白质类物质。通过场发射扫描电子显微镜（FE-SEM）可观察到细菌细胞出现形态损伤，经肠球菌素处理的细胞表现出细胞膜破损与结构解体现象。后续能量色散X射线光谱（EDX）分析验证了离子渗漏与细胞损伤的发生，而最小杀菌浓度（MBC）实验则证实该肠球菌素具有强效杀菌活性。上述研究结果表明，海氏肠球菌产生的肠球菌素可通过破坏细胞膜发挥显著杀菌活性，有望成为针对革兰氏阳性菌与革兰氏阴性菌的新型抗菌制剂。