植物乳杆菌DY6主要抑菌代谢物的分析和鉴定

【背景】被广泛应用于食品和饲料等多个行业的乳酸菌已成为制作生物防腐剂的研究热点。【目的】探究抑菌性能良好的植物乳杆菌DY6的抑菌物质,为其进一步应用提供参考依据。【方法】对植物乳杆菌发酵液中抑菌物质的理化特性进行研究,采用GC-MS分析发酵上清液代谢物,通过多元统计学分析方法推测主要抑菌物质,抑菌物质通过半制备进行初步分离后用GC-MS鉴定。【结果】植物乳杆菌DY6对金黄色葡萄球菌、大肠杆菌、沙门氏菌都有较强的抑制作用。采用不同发酵时间的发酵液作为研究对象,测定发酵上清液的抑菌能力,发酵0-4 h上清液无抑菌能力,发酵至8 h抑菌能力逐步上升,发酵24-48 h发酵上清液抑菌能力趋于稳定,在48 h时抑菌能力最佳,抑菌直径为15.28mm。通过多元统计学分析乳酸菌发酵液差异标志物,发现主要差异物为有机酸(如乳酸、乙酸、丙酸等)和脂肪酸(如辛酸、癸酸等)。经过半制备液相分离发酵上清液得到的抑菌组分,主要有有机酸(如乳酸、乙酸、3-苯基乳酸、苯丙酸等)和脂肪酸(如癸酸、辛酸、壬酸等),另外还有少量的醛类和醇类物质。【结论】确定了植物乳杆菌DY6的抑菌物质主要为有机酸和脂肪酸,为其进一步防腐应用提供了理论基础。

Analysis and identification of main antibacterial metabolites secreted by Lactobacillus plantarum DY6

Background] Lactic acid bacteria, which are widely used in many industries such as food and feed, have become research hotspots for making biological preservatives. Objective] The antibacterial substance of Lactobacillus plantarum DY6, with the excellent antibacterial effect, was preliminarily explored, which would provide a reference for further application. Methods] The physicochemical properties of the antibacterial substances in the fermentation broth of Lactobacillus plantarum were studied. The GC-MS metabolomics method was used to analyze the metabolites in the fermentation supernatant, while the main inhibitory substances were speculated by multivariate statistical analysis and initially separated by semi-preparation HPLC for further identification by GC-MS. Results] Lactobacillus plantarum DY6 had strong inhibitory effect on Staphylococcus aureus, Escherichia coli and Salmonella. The antibacterial ability of fermentation supernatant with different fermentation time was tested. The supernatant of 0?4 h had no antibacterial activity, and the antibacterial ability was gradually increased after 8 h. The antibacterial activity of fermentation supernatant tended to be stable from 24 h to 48 h and was the best at 48 h. The antibacterial diameter was 15.28 mm. The differential markers of lactic acid bacteria fermentation broth were analyzed by multivariate statistical analysis. The main differences were found to be organic acids (such as lactic acid, acetic acid, propionic acid, etc.) and fatty acids (such as caprylic acid and citric acid). Antibacterial components of fermentation supernatant were obtained via semi-preparation HPLC, mainly including: organic acids (such as lactic acid, acetic acid, 3-phenyl lactic acid, phenylpropionic acid, etc.), fatty acids (such as citric acid, octanoic acid, citric acid, etc.), in addition to a small amount of aldehydes and alcohols. Conclusion] It was determined that the antibacterial substances of Lactobacillus plantarum DY6 were mainly organic acids and fatty acids, which provided a theoretical basis for further antiseptic applications.