抑制青霉菌乳酸菌的分离、鉴定及抑菌物质分析

Isolation and Identification of Lactic Acid Bacteria Inhibiting Penicillium and Analysis of Their Antimicrobial Components

目的:从市售酱菜中筛选具有抑制青霉菌活性的乳酸菌,测定其对酱菜中主要霉菌及产毒真菌的抑菌效果,分析乳酸菌抑制青霉菌的有效成分,并对乳酸菌进行分子生物学鉴定。方法:采用双层平板法对酱菜中具有抑制青霉菌活性的乳酸菌进行筛选,打孔法测定其抑制青霉菌作用,并采用蛋白酶消化、调节pH值、热处理等方法分析抑菌物质的有效成分,采用16S rDNA聚合酶链式反应扩增后测序对乳酸菌进行鉴定。结果:从酱菜中筛选出的14株乳酸菌中,其中3株对酱菜中分离的青霉菌及2株产毒真菌的生长有较明显的抑制作用,不同蛋白酶处理、pH值调节对乳酸菌发酵浓缩液的抑菌活性会有不同影响,但是3种加热处理并不改变抑菌效果。3株乳酸菌经鉴定分别为:弯曲乳杆菌(Lactobacillus curvatus)、清酒乳杆菌(Lactobacillus sake)、植物乳杆菌(Lactobacillus plantarum)。结论:从酱菜中分离的乳酸菌对酱菜中青霉菌及某些产毒霉菌的生长有明显抑制作用,推测其抑菌成分可能为小分子肽和/或有机酸。

Objective： The aim of this study was to isolate and identify lactic acid bacteria able to inhibit Penicillium from various pickles. The antibacterial activity was determined against the dominant molds in pickles and toxin-producing fungi and the active compounds produced by the obtained isolates against Penicillium were analyzed. The molecular biological identification of strains was performed by molecular biological methods. Methods： By the double-layer plate method, lactic acid bacteria with antimicrobial activity against Penicillium were screened from the pickles. The inhibitory effects of lactic acid bacteria against fungi from the pickles and mycotoxin-producing fungi preserved in our lab were determined, and the active substances from lactic acid bacteria were analyzed by protease digestion, pH adjustment and heating. These lactic acid bacteria were then identified via 16 S rDNA sequence analysis after PCR amplification. Results： Three strains were screened from 14 dominant lactic acid bacterial strains isolated from the pickles for high inhibitory activity against fungi isolated from the pickles and 2 toxigenic fungi. Treatment with different proteases and p H adjustment had different effects on the antibacterial activity of the concentrated culture supernatant of lactic acid bacteria, while three heat treatments did not affect the inhibitory efficiency. Three lactic acid bacteria were identified as L. curvatus, L. sakei and L. plantarum, respectively. Conclusion： Lactic acid bacteria screened from pickles have high inhibitory activity on Penicillium and some toxigenic fungi, suggesting that the strains can be used as biological preservative to extend the shelf life of pickles, and its antibacterial ingredients may be small peptides and/or organic acids.