针铁矿—产甲烷体系内微生物代谢产物的作用研究

发布时间：2018-10-12 08:50

【摘要】：在废水生物处理过程中微生物代谢产物对于生物聚集体形成及污染物转化分解具有十分重要的影响。近年来,铁氧化物强化厌氧产甲烷过程得到了国内外研究学者的广泛关注,但微生物代谢产物在此过程中的作用却鲜有报道。因此,本研究通过构建针铁矿-厌氧产甲烷体系,利用不同规格的透析袋富集微生物代谢产物,进而考察反应体系甲烷产生效率及微生物群落的变化;以Shewanella oneidensis MR-1为对象,考察分析不同形态铁还原体系内微生物代谢产物的产生特征;构建产甲烷菌-铁还原菌-针铁矿体系,利用iTRAQ蛋白质组学技术对添加针铁矿-产甲烷体系的微生物代谢产物进行分析,利用高通量测序技术对微生物群落进行了分析表征,得到的主要结论如下:1)使用透析袋有利于提高针铁矿和微生物之间的接触,但孔隙较大的透析(10kDa)对于产甲烷速率影响不大。而使用孔隙较小的透析袋(2000Da)显著的提高了SMP浓度和产甲烷速率,SMP及其中的黄素类物质可能在促进产甲烷过程起到重要的作用。微生物群落分析表明SMP的富集不仅提高了体系内具有电化学活性的微生物相对丰度,而且也促进了乙酸型产甲烷菌Uncultured Methanosaeta sp.的生长。2)以Shewanella oneidensis MR-1为研究对象,研究不同导电材料对铁还原效率、微生物代谢产物及黄素类物质分泌的影响,探究添加针铁矿的产甲烷体系中可能的铁还原行为。结果发现,导电材料对于S.oneidensis MR-1还原针铁矿的影响主要由影响电子传递效率及菌体活性两方面组成。针铁矿刺激S.oneidensis MR-1在培养初期分泌更多的微生物代谢产物,而导电材料的添加降低了S.oneidensis MR-1微生物代谢产物中黄素类物质的比例。CNTs有效促进了S.oneidensis MR-1对游离态铁Fe-NTA的还原,石墨对S.oneidensis MR-1还原针铁矿有一定的促进作用。3)高通量分析结果显示针铁矿可以调节微生物群落功能。分泌蛋白和微生物群落分析结果显示,针铁矿显著促进了末端产甲烷代谢途径及胞外电子转移/氧化还原相关的过程,Firmicutes门、Anaerolinaceae科及Synergistetes门微生物参与了针铁矿促进产甲烷的过程。同时针铁矿的添加使得以乙酸盐为底物的产甲烷体系实现氢型产甲烷过程。iTRAQ蛋白质组学分析结果表明SMP蛋白主要来源于微生物自身裂解。
[Abstract]:Microbial metabolites play an important role in the formation of biological aggregates and the transformation and decomposition of pollutants during the biological treatment of wastewater. In recent years, the enhancement of anaerobic methanogenic process by iron oxides has received extensive attention from domestic and foreign researchers, but the role of microbial metabolites in this process is rarely reported. Therefore, through the construction of goethite-anaerobic methanogenic system, the microbial metabolites were enriched with different dialysate bags, and the methane production efficiency and microbial community changes of the reaction system were investigated. Shewanella oneidensis MR-1 was used as the object. The production characteristics of microbial metabolites in different forms of iron reduction system were investigated and analyzed, and the methanogenic bacteria, iron reducing bacteria and goethite system were constructed. ITRAQ proteomics technique was used to analyze the microbial metabolites in the system of pyrite and methane production, and the microbial community was characterized by high-throughput sequencing technique. The main conclusions are as follows: 1) the use of dialysis bags can improve the contact between goethite and microbes, but the larger porosity dialysis (10kDa) has little effect on methanogenic rate. However, the concentration of SMP and methanogenic rate were significantly increased by using dialysate bag (2000Da) with small porosity. SMP and its flavonoids may play an important role in the process of methanogenesis. Microbial community analysis showed that the enrichment of SMP not only increased the relative abundance of microorganisms with electrochemical activity in the system, but also promoted Uncultured Methanosaeta sp. of methanogenic bacteria of acetic acid type. 2) the effects of different conductive materials on iron reduction efficiency, microbial metabolites and the secretion of flavin were studied with Shewanella oneidensis MR-1 as the research object, and the possible iron reduction behavior in methanogenic system with goethite was explored. The results show that the effect of conductive materials on the reduction of goethite by S.oneidensis MR-1 is mainly composed of two aspects which affect the efficiency of electron transport and the activity of bacteria. Goethite stimulated S.oneidensis MR-1 to secrete more microbial metabolites at the early stage of culture, while the addition of conductive materials decreased the ratio of xanthins in S.oneidensis MR-1 microbial metabolites. CNTs effectively promoted the reduction of free iron Fe-NTA by S.oneidensis MR-1. Graphite can promote the reduction of goethite by S.oneidensis MR-1. 3) the results of high throughput analysis show that goethite can regulate the function of microbial community. The results of secretory protein and microbial community analysis showed that goethite significantly promoted end-methanogenic pathway and extracellular electron transfer / redox related processes. Microbes of Firmicutes gate, Anaerolinaceae family and Synergistetes gate were involved in the process of goethite promoting methanogenesis. At the same time, the addition of goethite made the methanogenic system with acetate as the substrate to realize the process of hydrogen methanogenesis. The results of iTRAQ proteomics analysis showed that the SMP protein was mainly derived from microbial self-cleavage.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ221.11;X703

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