自然发酵甘薯酸浆细菌动态规律解析及乳酸菌絮凝性研究

发布时间：2018-04-19 13:18

  本文选题：甘薯酸浆 + 高通量测序　； 参考：《沈阳农业大学》2017年硕士论文

【摘要】：甘薯酸浆是粉丝或淀粉生产中天然形成的副产物,是一种微生物絮凝剂。在淀粉生产的过程中加入酸浆,可以加速淀粉与蛋白质的分离。但传统的酸浆法生产淀粉多数靠经验,经常会受到一些条件影响。所以,酸浆质量极不稳定,在一定程度上影响了淀粉生产的产量和质量。因此,了解影响酸浆发酵的因素,掌握自然发酵甘薯酸浆中的微生物菌群结构,对提高酸浆质量,开发微生物絮凝剂,减少酸浆的使用量,解决环境污染问题具有有重要的意义。本试验以自然发酵甘薯酸浆为研究对象,采用高通量测序法对不同发酵时期的酸浆样品进行细菌类群动态规律分析,解析各细菌类群与酸浆絮凝性的关系。结果表明:自然发酵甘薯酸浆主要以厚壁菌门Firmicutes(92.6%)、变形菌门Proteobacteria(3.6%)和蓝藻细菌门Cyanabacteria(3.4%)为主。其中厚壁菌门主要以乳杆菌属Lactobaillus(55.3%)、明串珠菌属Leuconostoc(23.8%)、芽孢杆菌属Bacillis(2.9%)为主。变形菌门主要以假单胞菌属Pseudomonas(2.0%)为主。因此,乳杆菌属是自然发酵甘薯酸浆中优势菌,明串珠菌属为次优势菌。随着发酵时间的延长,乳杆菌属含量先减少后增加,在发酵中期最低。而明串珠菌属含量先增加后减少,在发酵中期最高,且在发酵中期时自然发酵甘薯酸浆絮凝率最高,因此明串珠菌属为自然发酵甘薯酸浆中的絮凝作用菌。根据对甘薯酸浆自然发酵过程中的细菌类群动态规律解析结果,分离并鉴定酸浆中具有絮凝性的细菌类群,并验证其功能。结果表明:从自然发酵甘薯酸浆中共分离出55株疑似乳酸菌,革兰氏染色均为阳性、过氧化氢酶反应均为阴性,初步鉴定均为乳酸菌。经16SrDNA鉴定,均为明串珠菌属。共包括3种明串珠菌属,分别为:Leuconostoc mesenteroides(76.36%)、Leuconostocpseudomesenteroides(20%)、Leuconostoc sp.(3.64%)。酸浆发酵整个过程的优势菌株为Leuconstoc mesenteroides,絮凝率最高时优势菌株为Leuconostoc mesenteroides。
[Abstract]:Sweet potato acid pulp is a kind of microbial flocculant, which is a natural by-product in the production of vermicelli or starch.The separation of starch and protein can be accelerated by adding acid pulp in the process of starch production.However, most of the traditional acid sizing process starch production depends on experience, often affected by some conditions.Therefore, the quality of acid pulp is very unstable, which to some extent affects the yield and quality of starch production.Therefore, we should understand the factors that affect the fermentation of sour pulp, master the structure of microbial flora in naturally fermented sweet potato and acid pulp, improve the quality of acid pulp, develop microbial flocculant, and reduce the amount of acid pulp.It is of great significance to solve the problem of environmental pollution.In this experiment, the natural fermented sweet potato acid pulp was used as the research object. The dynamic laws of bacterial groups in different fermentation stages were analyzed by high-throughput sequencing method, and the relationship between the bacterial groups and the flocculability of acid pulp was analyzed.The results showed that the natural fermented sweet potato pulp was mainly composed of phylum firmicutes92.6g, Proteobacteria Proteobacteria 3.6B) and Cyanabacteria cyanabacteria 3.4.Among them, Lactobacillus Lactobacillus 55.3, Leuconostoctus 23.8m and Bacillis2.9.The phylum of Proteus was mainly Pseudomonas 2.0).Therefore, Lactobacillus is the dominant bacteria in natural fermentation sweet potato pulp, and Streptococcus spp is secondary dominant.With the increase of fermentation time, the content of Lactobacillus decreased first and then increased, and was the lowest in the middle stage of fermentation.However, the content of Streptomyces increased first and then decreased, and reached the highest in the middle stage of fermentation, and the flocculation rate of natural fermented sweet potato and acid pulp was the highest.Based on the analysis of the dynamic laws of bacterial groups during the natural fermentation of sweet potato acid pulp, the flocculating bacteria groups in sweet potato pulp were isolated and identified, and their functions were verified.The results showed that 55 strains of suspected lactic acid bacteria were isolated from naturally fermented sweet potato pulp. Gram staining was positive, catalase reaction was negative, and all were identified as lactic acid bacteria.All of them were identified as Streptococcus by 16SrDNA.There are three species of Leuconostoc mesenteroides76.36 in the genus Leuconostoc, Leuconostock-pseudomes enteroides20 and Leuconostoc sp.Leuconstoc mesenteroides was the dominant strain in the whole fermentation process, and the dominant strain was Leuconostoc mesenteroides when the flocculation rate was the highest.
【学位授予单位】：沈阳农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TS201.3;TQ920.1
，

本文编号：1773252