抑制阪崎肠杆菌的乳酸菌筛选及其抗菌物质特性研究

目的 从酸菜和大弹涂鱼肠道中分离可产抑制阪崎肠杆菌活性的乳酸菌，并对抑菌物质的特性和抑菌机制进行研究，为其在食品保鲜中的应用奠定基础。方法 利用抑菌圈试验从分离所得的多株乳酸菌中筛选具有抑制阪崎肠杆菌活性的菌株并鉴定，排除酸及过氧化氢的影响后，分析其抑菌产物的特性。分离纯化抑菌物质，并初步探讨抑菌机制。结果 筛选得到一株抑菌效果最好的乳酸菌SA3，经鉴定为发酵黏液乳杆菌(Limosilactobacillus fermentum)，其上清液对阪崎肠杆菌抑菌圈直径达到16.94 mm。上清液具有蛋白特性和热稳定性，以乙酸乙酯粗提出的抑菌物质对鼠伤寒沙门氏菌、白色念珠菌、大肠埃希氏菌等致病菌表现出较强抑菌活性。其抑菌机制为乳酸菌所产抑菌物质可破坏阪崎肠杆菌的细胞壁及内容物。结论 本研究分离到的发酵黏液乳杆菌SA3有望应用于乳制品中阪崎肠杆菌的生物防腐。

Screening of lactic acid bacteria against Enterobacter sakazakii and study on the properties of their inhibitory substances

Objective Isolation of lactic acid bacteria from the intestinal tract of sauerkraut and large mudskipper that can produce inhibitory activity of Enterobacter sakazakii, and study of the characteristics of the inhibitory substances and the mechanism of inhibition, laying the foundation for their application in food preservation. Methods The strains with inhibitory activity against Enterobacter sakazakii were screened and identified from the isolated lactic acid bacteria using the circle of inhibition test, and their inhibition products were characterized after excluding the effects of acid and hydrogen peroxide. Isolation and purification of inhibition substances and preliminary exploration of inhibition mechanisms. Results A strain of Lactobacillus SA3, identified as Limosilactobacillus fermentum, with an inhibition circle diameter of 16.94 mm against E. sakazakii, was identified as the most effective. The supernatant was characterised by its protein properties and thermal stability, and the bacteriocins were extracted with ethyl acetate. Bacteriocin shows strong antibacterial activity against pathogenic bacteria such as Salmonella typhimurium, Candida albicans and Escherichia coli. The mechanism of bacterial inhibition is that the bacteriostatic substances produced by lactic acid bacteria can destroy the cell wall and contents of Enterobacter sakazakii. Conclusion The Lactobacillus fermentum SA3 isolated in this study is expected to be used for the biological antiseptic of E. sakazakii in dairy products.