小米自然发酵菌株的鉴定及发酵菌株特性分析  

Identification of and characteristics of bacterial strains for natural fermentation of millet starch

作　　者：寇芳[1] 李文杰[1] 沈蒙[1] 宁冬雪 夏甜天 葛云飞[1] 王维浩[1,2] 曹龙奎 KOU Fang LI Wen-jie SHEN Meng NING Dong-xue XIA Tian-tian GE Yun-fei WANG Wei-hao CAO Long-kui(College of Food Science, Heilongjiang Bayi Agricultural University, Daqing 163319, Heilongjiang Province, China)

机构地区：[1]黑龙江八一农垦大学食品学院,黑龙江大庆163319 [2]国家杂粮工程技术研究中心,黑龙江大庆163319

出　　处：《中国生物制品学杂志》2017年第9期931-935,942,共6页Chinese Journal of Biologicals

基　　金：国家重点研发计划"杂粮活性组分在加工过程中的调控与活性保持技术与应用"(2017YFD0401203);黑龙江省重大科技攻关项目"杂粮绿色食品精深加工与品质控制关键技术研究"(GA15B301);黑龙江八一农垦大学研究生创新科研项目(YJSCX2017-Y54)

摘　　要：目的自然发酵筛选对小米改性起主要作用的菌种,并对发酵菌株的特性进行分析。方法用培养基筛选小米自然发酵液中主要菌种,分离纯化后,进行菌株生理生化鉴定、26S r DNA、16S r DNA序列测定,菌株纯培养后的p H、微生物菌落数曲线绘制,发酵菌株有机酸含量检测,并对不同菌株的产酸、产胞外淀粉酶的能力进行检测。结果从自然发酵液中筛选出的菌种主要为植物乳杆菌(Lactobacillus plantarum)、戊糖片球菌(Pediococcus pentosaceus)、屎肠球菌(Enterococcus faecium)、酿酒酵母(Saccharomyces cerevisiae)、芽孢菌(Bacillus)。植物乳杆菌在发酵12 h时菌落数达到生长的指数期,之后p H迅速下降;戊糖片球菌及屎肠球菌在发酵24 h时菌落数达到生长的指数期,之后p H迅速下降,培养40 h时戊糖片球菌的p H明显低于二者;酿酒酵母及芽孢菌在发酵36 h时菌落数达到生长的指数期,之后p H略有下降。相同时间内,戊糖片球菌的产酸能力>植物乳杆菌>屎肠球菌,而酿酒酵母和芽孢杆菌不具产酸能力;戊糖片球菌有较强的产酒石酸及乳酸的能力,植物乳杆菌具有产酒石酸及乳酸的能力,但弱于戊糖片球菌,而屎肠球菌有较强的产乳酸的能力;植物乳杆菌、戊糖片球菌、屎肠球菌、酿酒酵母不能产胞外淀粉酶,而芽孢杆菌具有较强的淀粉降解能力。结论确定了自然发酵小米中的主要菌种,为研究自然发酵小米淀粉老化特性等奠定了基础。Objective To screen the bacterial strains which play important roles in improvement of characteristics of millet starch by natural fermentation, and analyze their characteristics. Methods The major bacterial strains in fermentation liquid of millet starch were isolated and purified for physiological and biochemical identifications, 26 S r DNA and 16 S r DNA sequencing, determination of p H value after pure culture, plotting of microorganism colony count curve and determination of organic acid content. The abilities of various bacterial strains in production of acids and amylase were evaluated. Results The bacterial strains screened from the natural fermentation liquid were mainly Lactobacillus plantarum, Pediococcus pentosaceus, Enterococcus faecium, Saccharomyces cerevisiae and Bacillus. The colony count of L. plantarum reached the level of exponential growth phase 12 h after fermentation, while the p H value decreased rapidly afterwards. However, the colony counts of P. pentosaceus and E. faecium reached the levels of exponential growth phase24 h after fermentation, while the p H value decreased rapid afterwards. The p H value of P. pentosaceus 40 h after fermentation was significantly lower than those of L. plantarum and E. faecium. The colony counts of S. cerevisiae and Bacillus reached the levels of exponential growth phase 36 h after fermentation, while the p H value decreased slightly. In the turn of acid-producing ability within the same time duration, the bacterial strains were P. pentosaceus, L. plantarum and E. faecium, while S. cerevisiae and Bacillus showed no acid-producing abilities. P. pentosaceus showed high abilities in productions of tartaric acid and lactic acid, while such abilities of L. plantarum were lower than those of P. pentosaceus.However, E. faecium showed high ability in production of lactic acid. L. plantarum, P. pentosaceus, E. faecium and S. cerevisiae showed no ability in production of excellular amylase, whille Bacillus showed high ability in digestion of starch. Conclusion The

关 键 词：小米 自然发酵 菌株鉴定 特性分析 

分 类 号：Q939.97[生物学—微生物学]