青贮苜蓿中抑菌活性乳酸菌的筛选及鉴定

Isolation and identification of lactic acid bacteria with antibacterial activity from alfalfa silage

研究旨在从苜蓿青贮材料中筛选出有高效抑菌活性的乳酸菌,并分析其抑菌机理。实验从苜蓿青贮材料中分离出104株乳酸菌通过牛津杯双层平板法筛选得到两株具有高效抑菌活性的菌株;在对其抑菌活性进行初步分析后发现,其中一株菌发挥抑菌活性的主要成分为蛋白类物质,另一株菌发挥抑菌活性的主要成分为有机酸。经过生理生化、碳源发酵及16S r DNA序列同源性分析,这两株乳酸菌分别被鉴定为Enterococcus mundtii及Lactobacillus plantarum。两株菌的抑菌活性物质在pH值范围及温度范围分别表现出广泛的耐受性,表明它们在苜蓿青贮中具有潜在的应用价值。

The objective of this study was to screen lactic acid bacteria with strong antibacterial activi- ty from alfalfa silage, and analysis its mechanism. 104 lactic acid bacteria strains were isolated from al- falfa silage, two strains of them with strong antibacterial activity were screened by dual-culture agar plate assay. After a preliminary analysis, the main antibacterial component of one strain was found to be protein, the other was organic acid. Based on phenotypic, biochemical tests, the results of carbon source fermentation and 16S rDNA sequence homology analysis, one of the strains were identified as Enterococcus mundtii, the other was identified as Lactobacillus plantarum. The widely toleration to pH range and temperature range respectively of the two strains antibacterial substances indicate their po- tential application value in silage fermentation.