人源耐酸双歧杆菌的筛选及其性能评价

发布时间：2018-04-18 11:17

本文选题：人源双歧杆菌 + 酸致死筛选　；参考：《上海交通大学》2012年硕士论文

【摘要】：双歧杆菌是人和动物体内十分重要的益生菌群之一,目前,双歧杆菌的益生作用已经得到普遍认可,益生菌产品也得到了越来越广泛的研究和应用。益生菌制剂在服用过程中,需要保证一定剂量活的菌体最终进入人体肠道,才能对宿主产生益生作用,而人源双歧杆菌对胃部的低pH酸环境是高度敏感的。筛选出更加耐酸的人源双歧杆菌对双歧杆菌益生菌制品的生产应用具有重要意义。目前,用于提高菌株耐酸性的主要方法是用亚致死酸性条件短时间处理而使菌株增强耐酸性,可是已有研究表明这一方法并不适用于双歧杆菌。我们需要找出一种有效的方法来解决这一问题。本实验采用了将双歧杆菌长时间暴露在致死低pH环境下的酸致死筛选方法,用两种不同的处理顺序,从健康儿童的新鲜粪便中,筛选出了22株人源双歧杆菌,并分别对其进行了种属的分子鉴定和耐酸性能的评价,选出了耐酸性能最优的2株长双歧杆菌SQS7-31与SQS4-64。通过对这两株长双歧杆菌连续20代的无压力传代后的耐酸性能评价,研究其耐酸性能的遗传稳定性,比较两种不同的筛选处理顺序对耐酸菌株筛选结果的影响。研究结果表明这两株长双歧杆菌的耐酸性能可稳定遗传,直接对人体粪便通过酸致死处理来筛选双歧杆菌和先在温和条件下从粪便选出菌株再进行酸致死处理和筛选,均可以获得具有遗传稳定性的优良耐酸菌株。这个研究结果也验证了对已有文献相关论点的质疑,说明并非只有直接对人体粪便进行酸致死处理筛选才可获得优势耐酸双歧杆菌菌株。通过观察两株菌在不同胆汁盐浓度下生长迟滞情况对其耐胆汁盐性能进行评价;通过观察两株菌对超氧阴离子的清除能力,对它们的抗氧化性能进行评价;通过亚致死温度的短时间处理,对这两株耐酸菌株的耐热性能进行评价;通过计量菌体在模拟消化道中的幸存率,评价它们对人体不利环境的耐性。综合所有的评价结果,最终选出长双歧杆菌SQS7-31做为潜在的商业化生产菌株,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并申请了发明专利。目前,耐酸性能优良的长双歧杆菌SQS7-31已经被上海交大昂立股份有限公司做为生产备用菌株。
[Abstract]:Bifidobacterium is one of the important body of human and animal probiotics at present, probiotics Bifidobacterium has been widely recognized, probiotic products have also been studied and applied more and more widely. Taking probiotics in the process, need to ensure that a certain dose of living cells eventually enter the human gut, can produce probiotic effects on host pH, while the low acid environment of the stomach of human Bifidobacterium is highly sensitive. Screening is important to production application of bifidobacteria from more acid on Bifidobacterium probiotic products. At present, the main methods for improving strains resistant to acid is a short treatment with sublethal acidic conditions make enhanced acid resistant strains however, studies have shown that this method is not suitable for Bifidobacterium. We need to find an effective method to solve this problem.
This experiment used the Bifidobacterium long time exposed to lethal low pH environment acid lethal screening method, using two different processing order, from the fresh feces of healthy children, 22 strains were screened out from Bifidobacterium, and were evaluated for molecular identification and acid resistance of the genus choose the optimal acid resistance, 2 strains of Bifidobacterium longum SQS7-31 and SQS4-64. acid through performance evaluation without pressure after passage of the two strains of Bifidobacterium longum for 20 generations, the genetic stability of the acid resistance, compare two different screening treatment sequence of acid resistant strain screening results. The results of the study show that acid the performance of these two strains of Bifidobacterium longum genetic stability, directly to the human feces by acid lethal treatment screening of Bifidobacterium and under mild conditions were selected from waste acid treatment and screening of death Choose, can obtain excellent acid resistant strains with genetic stability. The results also verify the question of literature related argument, that it is not only directly on human waste acid treatment can be lethal screening aciduric Bifidobacterium strains. Through the observation of two strains of bacteria grown in different bile salt concentration hysteresis was evaluated the bile salts resistance performance; through the observation of two strains of superoxide anion scavenging ability, to evaluate their antioxidant properties; through the short time of sublethal temperature treatment, to evaluate these two strains of acid resistant strains by measuring heat resistance; bacteria in simulated digestive tract in the evaluation of their survival rate, the adverse environmental tolerance. All comprehensive evaluation results, and ultimately selected Bifidobacterium longum SQS7-31 strains as commercial production potential, the strain in Chinese. Physical culture preservation Management Committee General Microbiology center preservation and applied for a patent. At present, Bifidobacterium longum SQS7-31 excellent acid resistance has been Shanghai only Limited by Share Ltd as the production of spare strain.

【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R371

【引证文献】