纳豆菌的分离、筛选、鉴定及发酵特性对比研究

Study on the Separation,Screening and Identification of Bacillus natto and the Comparison of Its Fermentation Characteristics

为考察不同地区的纳豆菌在发酵食品纳豆方面的异同,研究以日本顺食真、北京燕京及大连美屋的鲜纳豆作为供试材料,从3个地区的鲜纳豆中共分离得到了17株菌,根据菌落形态特征初筛,对产蛋白酶相对活性进行复筛,各得到1株蛋白酶活性较高的菌株A1,B2,C2;经生理生化试验证实均为纳豆菌。利用3株纳豆菌发酵纳豆,对纳豆产品从拉丝长度、粘液产率、纳豆活菌数及其他感官指标方面进行了考察。结果表明:纳豆菌C2在发酵纳豆过程中,活菌数增殖最快,粘液产率最高,拉丝长度最长;纳豆菌B2在发酵过程中活菌数增殖最慢,尽管发酵的纳豆中活菌数最高,但粘液产率及拉丝长度均不理想。

In order to investigate the differences of fermented strains from different regions,Shunshizhen natto from Japan,Meiwu natto from Dalian,Yanjing natto from Beijing are selected as the tested materials.17 strains of suspected Bacillus natto are isolated,A1,B2,C2 with high activities of protease activity are obtained after colonies morphology characteristics tests and skim milk hydrolysis tests.All of them are identified to be Bacillus natto by physiological and biochemical tests.The wire drawing,the yield of natto mucus,the number of Bacillus and other sensory indicators of products are examined after fermented by the 3 isolated Bacillus natto.The results show that during the fermentation process,the viable count growth rate of Bacillus C2 is the fastest,the yield of mucus is the highest and the length of wire drawing is the longest,the viable count growth rate of Bacillus B2 is the lowest,although the number of Bacillus B2 is the highest,the yield of mucus and the wire drawing length are not ideal.