市售纳豆产品中菌株的分离、鉴定及纳豆激酶活力比较

Separation and identification of commercial natto strain species and comparision of nattokinase activity

为考察不同品牌纳豆中纳豆芽孢杆菌的异同,本研究选取了三个产地六个品牌的纳豆产品作为试材,分别是日本的北海道、御城、竹炭、木场水户纳豆,北京的燕京纳豆和大连的美屋纳豆。从这六种品牌的纳豆中分离纯化得到了15个具有纳豆芽孢杆菌典型菌落特征的单菌落,并且与模式菌株1.1086株分别从菌落形态、菌株的细胞形态和生理生化实验以及16S rRNA序列分析四个方面进行对比鉴定。结果表明,这15株芽孢杆菌都为纳豆芽孢杆菌,其中10株与模式菌株的16S rRNA序列有99%的同源性,3株是98%,2株是97.5%。并且对挑选出的15株纳豆芽孢杆菌采用琼脂糖-纤维蛋白平板的方法测定纳豆激酶的活性,结果表明NB-8和NB-12具有较高的纳豆激酶活性,酶活力分别达到了1076.663 U/m L和1073.85 U/mL。

In order to investigate the difference of fermentation strain from different kind of natto, six brands of natto products from three origins were selected, which were Meiwu, Yucheng, Yanjing, Bamboo charcoal, Hokkaido and Benchangshuihu. Fifteen typical colonies of Bacillus subtilis strains with the characteristics of a single colony were isolated from six Natto food produced.They were compared with model strain Bacillus subtilis Natto 1.1086 according to their morphological,physiological, biochemical characters and 16S rRNA sequence of strain analysis respectively.Results showed that 15 bacterias were Bacillus subtilis strains,in which 10 strains present homology of 99%, 3 strains present 98% and 2 present homology 97.5% on 16S rRNA sequence. And the nattokinase of 15 Bacillus natto were measured by method of agarose-fibrin plate. The data indicate both of Nattokinase activity of NB-8 and NB-12 were relatively strong with a result of 1076.663 and 1073.85 U/mL, respectively.