花鲈鱼肠道中产细菌素粪肠球菌的筛选和抑菌效果研究

Identification and antibacterial activity of bacteriocin-producing Enterococcus faecalis isolated from Lateolabrax japonocus intestine

为筛选出产细菌素的乳酸菌,应用于低温物流水产品保鲜中以提高水产品的品质。从花鲈鱼肠道中分离出18株乳酸菌,以大肠杆菌为指示菌,采用牛津杯琼脂扩散法检测菌株的抑菌谱大小,并经过有机酸排除、H 2O 2排除、蛋白酶水解检测试验,最终筛选得到1株产细菌素的菌株。经形态学、生理生化分析以及16S rDNA序列同源性分析,鉴定该菌株为Enterococcus faecalis。该菌株可以抑制水产品中的一些腐败菌,比如希瓦氏菌和假单胞菌;而对杀鲑气单胞菌的抑菌作用最强。因此,该菌株可作为一种潜在的生物保鲜剂应用在水产品保鲜中,以延长水产品的货架期。

To improve the quality of aquatic products during low temperature preservation,bacteriocin-producing lactic acid bacteria were screened.There were 18 strains isolated from the intestine of perch(Lateolabrax japonocus),and their inhibitory ability on Escherichia coli was tested.By excluding the influences of organic acids,hydrogen peroxide and proteolysis,a bacteriocin-producing strain was obtained and identified as Enterococcus faecalis(E.faecalis)by morphological,physiological and biochemical analysis as well as 16S rDNA sequencing and homology analysis.Incubating the fermentation broth of E.faecalis with certain spoilage organisms from aquatic products,the strongest inhibitory effect was obtained on Aeromonas salmonicida,as well as relatively weaker effects on the strains of Shewanella and Pseudomonas.This study indicates the potential application of E.faecalis as a biological preservative in extending the shelf life of aquatic products.