鹅粪便中特基拉芽孢杆菌和类肠膜魏斯氏菌的分离鉴定

【目的】从鹅粪中分离芽孢杆菌属和乳杆菌属细菌,为鹅源功能菌研究和合理用药提供参考。【方法】收集30只50周龄健康北方白鹅的直肠粪便,利用特异性培养基和生化反应试验分离筛选菌株,筛选的菌株通过DNA提取、PCR扩增16S rDNA测序鉴定后,与GenBank中参考菌株进行比对构建进化树,进行相似性比对确定菌株种类。培养48 h后检测细菌的生长特性、最适酸碱度和温度,以pH 7.0、无胆盐环境下细菌生长状态为对照,检测其耐酸耐胆盐能力,并进行药敏试验检测其对抗菌药的耐受性。【结果】经分离筛选共获得9株细菌,通过生化试验最终选出2株菌,根据进化树的进化距离和相似性比对确定其分别是特基拉芽孢杆菌CC2FG2和类肠膜魏斯氏菌JY0R2。生长特性结果显示,特基拉芽孢杆菌CC2FG2在培养基pH为6.5、温度为30℃条件下培养16 h的增殖效果最好,可以耐受1.2%胆盐,活菌数是无胆盐的69.2%,耐酸特性比较强,培养基pH为3.5的强酸环境下活菌数是pH为7.0的81.5%;抗菌药耐受性结果显示,其对氧氟沙星、诺氟沙星、卡那霉素、链霉素、克拉霉素、红霉素、复方新诺明和万古霉素敏感,对头孢呋辛,头孢...     

乳酸乳球菌和魏斯氏菌的分离及鉴定

试验以生牛奶、自制泡菜水、青贮料、市售奶酪为样品,进行乳酸乳球菌和魏斯氏菌的筛选与鉴定。通过培养基中菌落形态观察和镜检细胞形态观察,共筛得6株疑似乳酸球菌（分别命名为ST1、ST2、ST6、ST7、ST8、ST9）。经生理生化、耐盐性、耐热性试验以及16S rD-NA序列分析鉴定,这6株菌分属两个属：ST1、ST2、ST7、ST9为乳酸乳球菌（Lactococcus lac-tis）,其中ST2为乳酸乳球菌乳脂亚种（Lactococcus lactis subsp. Cremoris）,ST7为乳酸乳球菌乳酸亚种（Lactococcus lactis subsp. Lactis ）;ST6、ST8属于魏斯氏菌属（Weissella）,其中ST6为食窦魏斯氏菌（Weissella cibaria）。研究表明,生牛奶和泡菜水分别是乳酸乳球菌和魏斯氏菌的优良生活环境,传统方法与分子生物技术相结合可更准确快速地分离及鉴定菌株。     

Isolation,Identification and Characterization of Lactic Acid Bacteria From Shao-jiou-luo (Fermented Zoned Cerith), a Traditional Fermented Food in Taiwan

This study investigated the distribution of the native lactic acid bacteria (LAB) population in shao-jiou-luo (fermented zoned cerith), a popular traditional fermented food in Taiwan. A total of 129 cultures of LAB were isolated from shao-jiou-luo samples, and 14 cultures were isolated from its main raw material, zoned cerith. These isolates were divided into classes by phenotype and then into groups by restriction fragment length polymorphism analysis and sequencing of 16S ribosomal DNA. The identification results revealed 11 bacterial species belonging to five genera in shao-jiou-luo and three species belonging to two genera in zoned cerith. The most common bacterial genera in shao-jiou-luo were heterofermentative Weissella and Leuconostoc. On the other hand, Enterococcus aquimarinus was the most common species found in the raw zoned cerith sample. In conclusion, the results suggest that heterofermentative LAB species greatly contributed to the fermentation of shao-jiou-luo. This is the first report describing the distribution and varieties of LAB that exist in the shao-jiou-luo fermentation process and raw zoned cerith.     

不同添加量产胞外多糖荞麦酸面团对面包烘焙和老化特性的影响

[目的]研究不同添加量的产EPS荞麦酸面团对面包烘焙和老化特性的影响。[方法]应用分离自酒曲中的产胞外多糖食窦魏斯氏菌T5发酵荞麦粉制成产胞外多糖荞麦酸面团和不产胞外多糖荞麦酸面团,比较2种酸面团的添加量对面包烘焙和老化特性的影响。[结果]食窦魏斯氏菌T5在添加蔗糖的条件下,发酵荞麦酸面团产生EPS的含量为9.36 g/kg;含有酸面团(20%和30%)的面包比容、硬度和感官评分都优于空白不含酸面团面包,且含有产EPS酸面团的面包品质更佳;随着酸面团添加量的增加,添加30%不产EPS酸面团对面包比容和硬度产生消极作用,而添加30%产EPS酸面团能改善新鲜面包品质;在相同贮藏期,含有不产EPS酸面团的荞麦面包随着酸面团添加量的增加,面包芯硬度和支链淀粉老化焓值显著增加,而添加30%产EPS酸面团对面包老化具有改善作用。[结论]该研究为开发营养、健康的高品质绿色烘焙发酵食品提供理论依据。