酱油渣中具有抑菌活性的乳酸菌的筛选及其抑菌特性

本研究以实验室前期从酱油渣中分离的16株乳酸菌ZW1~ZW16为出发菌株，拟筛选对大肠杆菌、金黄色葡萄球菌抑制效果较强的菌株，并对菌株产生的抑菌物质、生长特性及其影响因素进行分析。结果显示，乳酸菌ZW2、ZW9、ZW14对大肠杆菌、金黄色葡萄球菌均有较高的抑菌活性，其中ZW9抑菌效果最好，排除有机酸和H₂O₂影响后，胰蛋白酶、胃蛋白酶、蛋白酶K、α-蛋白酶、碱性蛋白酶、中性蛋白酶处理后抑菌活性均显著性降低（P<0.05），初步推断抑菌物质是一种具有蛋白质属性的细菌素。抑菌动力学曲线显示，菌株培养至20 h抑菌活性趋于稳定。抑菌稳定性显示，抑菌物质在40~100 ℃具有较好的热稳定性，在紫外线照射、表面活性剂处理下均保持较高的抑菌活性；在pH2.0~6.0抑菌活性无明显变化，pH10.0抑菌能力完全丧失。酱油渣中筛选的3株乳酸菌具有抑菌功能且产生的抑菌物质稳定，对开发成新型生物抑菌剂具有重要参考价值。

Screening of Lactic Acid Bacteria with Antibacterial Activity in Soy Sauce Residue and Its Antibacterial Properties

In this study, a total of 16 LAB strains, isolated from soy sauce residue in the early stage of our research group, were evaluated for their antibacterial activity against Escherichia coli and Staphylococcus aureus. In addition, the bacteriostatic substances and growth characteristics of these strains were investigated. The results showed that LAB strains ZW2, ZW9 and ZW14 exhibited high antibacterial activity against E. coli and S. aureus, of which ZW9 had the best antibacterial effect. After eliminating the interference factors such as the organic acids and hydrogen peroxides, three strains still maintained antimicrobial activity. However, the inhibitory activity decreased by the treatment with trypsin, pepsin, proteinase K, α-amylase, alkaline protease and neutral protease (P<0.05). Therefore, these strains might produce antimicrobial substances of proteinaceous character, i.e., bacteriocins. The three LAB strains showed maximum antibacterial activity and were fairly stable after 20 h of incubation by bacteriostatic profile analysis. The antibacterial substances exhibited a good thermal stability in 40~100 ℃ and kept their high antibacterial activity under ultraviolet irradiation and surfactant treatment. There was no significant decrease in antibacterial activity at pH2.0~6.0, and the antibacterial ability was completely lost at pH10.0. The three LAB strains from soy sauce residue exhibited good antibacterial activity and their antibacterial substances had good stability, which had important reference value for the development of new biological antimicrobial agents.