食品科学 ›› 2007, Vol. 28 ›› Issue (5): 185-190.

• 生物工程 • 上一篇    下一篇

传统干酪中一株产Ⅱa类细菌素乳酸菌的分离与鉴定

 刘国荣, 周康, 李平兰, 张金兰, 周伟   

  1. 中国农业大学食品科学与营养工程学院; 中国农业大学食品科学与营养工程学院 北京100083; 北京100083;
  • 出版日期:2007-05-15 发布日期:2011-12-31

Isolation and Identification of A Class IIa Bacteriocin-producing Lactic Acid Strain from Traditional Cheese

 LIU  Guo-Rong, ZHOU  Kang, LI  Ping-Lan, ZHANG  Jin-Lan, ZHOU  Wei   

  1. College of Food Science and Nutritional Engineering,China Agricultural University,Beijing 100083,China
  • Online:2007-05-15 Published:2011-12-31

摘要: 从内蒙古传统干酪中分离到一株产抑菌活性物质的乳酸菌M-2,其对单核细胞增生李斯特氏菌、金黄色葡萄球菌等食品中常见致病菌和腐败菌都有抑制作用。排除有机酸、H2O2等的干扰后,仍有抑菌活性:进一步硫酸铵沉淀、透析及浓缩处理后,其抑菌活性显著增强;用蛋白酶K处理后,其抑菌活性消失,因此确定该抑菌活性物质为蛋白类物质,进而确定乳酸菌M-2为细菌素产生菌。通过生理生化实验和16SrRNA基因序列分析对该菌株进行了鉴定。PCR扩增得到1675bp的16SrRNA序列,并将其通过BLAST软件在NCBI网站中进行同源性比,同时,通过Bioedit 7.0和Treedrawing软件绘制系统发育树。结果显示,M-2的16S rRNA序列和数据库中的屎肠球菌SF菌株的序列的同源性为99.87%。在细菌系统发育分类学上,M-2菌株归属屎肠球菌(Enterococcus faecium)。这与生理生化实验初步鉴定结果一致。根据细菌素的分类原则,将该细菌素归类为Ⅱa类细菌素。

关键词: 乳酸菌, Ⅱa细菌素, 屎肠球菌, 16SrRNA, 鉴定

Abstract: A lactic acid bacteria strain,M-2,producing inhibitory activity substance,is isolated from a Inner Mongolia traditional cheese.The bacteriocin shows a strong antimicrobial activity against most of the tested spoilage and food-borne pathogenic bacteria, such as Listeria monocylogenes,Staphylococcus aureus and so on.After eliminating some interference factors such as the organic acids,hydrogen peroxides and so on,the antimicrobial activity still exisits.By ammonium sulphate precipitation,dialysis and concentration,this substance is inactivated when treated with proteinase K.M-2 is identified Enterococcusfaecium on the base of physiological and biochemical characteristics and 16S rRNA gene sequences.The sequence fragment of 1675 bp 16S ribosomal RNA is amplified from total DNA of strain M-2 by PCR.The sequence analysis is completed by the application of BLAST on the websites of NCBI and the phylogenetic tree is drawn with Bioedit 7.0 with treedrawing.The results show that M-2 shares 99.87 % 16S rRNA sequence homology with Enterococcusfaecium strain SF.In phylogenetic framework of bacteria classification. strain M-2 belongs to Enterococcusfaeciurn.According to classification of bacteriocins,the bacterioncin belongs to classⅡa bacteriocins.

Key words: LAB, class IIa bacteriocin, Enterococcus faecium, 16SrRNA, identification