鼠李糖乳杆菌的筛

发布时间：2018-04-20 18:07

本文选题：益生菌 + 鼠李糖乳杆菌　；参考：《扬州大学》2006年硕士论文

【摘要】： 益生菌在促进人体健康和防止疾病发生中发挥着重要的作用。本论文从大量分离获得的乳酸菌菌株中,筛选具有优良特性的益生菌,并对其进行鉴定,为研究和开发具有自主知识产权的益生菌产品奠定基础。本论文从三个方面开展研究:即乳酸菌功能特性研究,以筛选获得性能良好的益生菌;对筛选获得的益生菌进行鉴定;益生菌加工特性研究。对分离的乳酸菌进行耐酸和耐胆汁酸盐试验,供试的15个菌株都能在pH3、0.3%胆汁酸盐中存活;供试菌株中有10个能在pH2、0.3%胆汁酸盐中存活5h,其中Q菌的生长情况最好,其耐受能力最强;在pH3、0.2%胆汁酸盐下只有Q菌能继续生长。对分离的乳酸菌进行了抑制致病性大肠杆菌和幽门螺旋杆菌的试验,通过研究供试菌株对大肠杆菌均有抑制作用,抑制作用最强的为Q菌,抑菌圈直径12.6mm,超过对照菌株BB-12的8mm。供试菌株大部分对幽门螺旋杆菌有抑制作用,抑制作用最强的为B菌,抑菌圈直径13mm,其次为Q菌12.7mm,对照菌株BB-12为9.8mm。对分离的乳酸菌进行了体外粘附能力试验,通过研究,供试菌株中对Caco-2细胞粘附能力最高的为A菌,其粘附平均值为18.7±5.92个/细胞,其次为Q菌12.9±2.74个/细胞,对照菌株BB-12为10.7±2.46个/细胞。先用乳酸菌粘附2h后,Q菌和E菌对大肠杆菌竞争粘附抑制力最强;先用大肠杆菌粘附2h,再用乳酸菌粘附,粘附数与空白大肠杆菌粘附数相差不大。对分离的乳酸菌进行了抗氧化试验,通过研究Q菌受试品喂服小鼠8天使得SOD活力增强,MDA含量有所降低,具有一定的抗氧化能力。在功能特性研究的基础上,对筛选获得的Q菌,进行初步鉴定。经传统的形态学观察及代谢产物气相色谱测定分析,Q菌归属于乳杆菌属(Lactobacillus)。通过API 50CHL试验条生理生化特性研究,鉴定Q菌99.9%为鼠李糖乳杆菌(Lactobacillus rhamnosus)。该菌株已在中国微生物菌种保藏管理委员会普通微生物中心保藏,保藏号为CGMCC No.1531,中国专利申请号为:200510111588.9,菌株名为鼠李糖乳杆菌LV108。在此基础上,进一步利用分子生物学方法对鼠李糖乳杆菌LV108进行了16S rRNA基因的扩增与测序,BLAST在线比对结果是:与菌株Lactobacillus rhamnosus MCRF-412和Lactobacillus rhamnosus MCRF-271 16S rRNA的基因序列只相差一个碱基,同源性高达99.9%。与全球最著名的益生菌Lactobacillus rhamnosus GG ATCC 53103的16S rRNA只相
[Abstract]:Probiotics play an important role in promoting human health and preventing disease. In this paper, probiotics with excellent characteristics were screened from a large number of isolated strains of lactic acid bacteria, which laid a foundation for the research and development of probiotic products with independent intellectual property rights. In this paper, three aspects of research are carried out: the study on the functional characteristics of lactic acid bacteria in order to select probiotics with good performance; the identification of the probiotics obtained by screening; and the study on the processing characteristics of probiotics. The acid tolerance and bile salt tolerance tests of the isolated lactic acid bacteria showed that all of the 15 strains were able to survive in pH3.3% bile salt, and 10 of the tested strains could survive in pH2.3% bile salt for 5 h, among which the growth of Q bacteria was the best. Its tolerance ability was strongest, and only Q bacteria could continue to grow at pH 3. 2% bile acid salt. The experiment of inhibiting pathogenic Escherichia coli and Helicobacter pylori was carried out on the isolated lactic acid bacteria. By studying the inhibitory effect of the tested strains on Escherichia coli, Q bacteria was the most effective. The diameter of inhibition circle was 12.6 mm, which was higher than that of the control strain BB-12 (8 mm). Most of the tested strains had inhibitory effect on Helicobacter pylori, the strongest inhibition was B, the diameter of inhibition circle was 13mm, the second was Q (12.7mm), the control strain BB-12 was 9.8 mm. The adhesion ability of isolated lactic acid bacteria to Caco-2 cells was tested in vitro. The results showed that A strain had the highest adhesion ability to Caco-2 cells, with an average adhesion of 18.7 卤5.92 cells per cell, followed by Q bacteria 12.9 卤2.74 cells per cell. The BB-12 of the control strain was 10.7 卤2.46 / cell. Lactic acid bacteria were used to adhere to E. coli for 2 hours, and then to E. coli for 2 hours, and then to lactic acid bacteria for 2 hours, the adhesion number was not different from that of blank Escherichia coli. The antioxidation test of isolated lactic acid bacteria was carried out. The SOD activity increased and the content of MDA decreased in mice fed with Q bacteria for 8 days. Based on the study of functional characteristics, the screening of Q bacteria was preliminarily identified. By traditional morphological observation and gas chromatographic analysis of metabolites, the bacteria belong to Lactobacillus. By studying the physiological and biochemical characteristics of the API 50CHL test strip, 99.9% of the bacteria were identified as Lactobacillus rhamnosus. The strain has been stored in the General microorganism Center of the Chinese microbial species Conservation Administration Committee under the name of CGMCC No. 1531, and the patent application number of China is 1: 200510111588.9. the strain is called Lactobacillus rhamnoides LV108. On this basis, the 16s rRNA gene of Lactobacillus rhamnoides LV108 was amplified by molecular biology and sequenced by blast online. The results showed that the gene sequence of Lactobacillus rhamnoides LV108 was only one base different from that of Lactobacillus rhamnosus MCRF-412 and Lactobacillus rhamnosus MCRF-271 16S rRNA. The homology is as high as 99.9. The 16s rRNA of Lactobacillus rhamnosus GG ATCC 53103, the most famous probiotic in the world
【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2006
【分类号】：R371

【引证文献】