厌氧氨氧化菌生长过程中的群体感应及作用机制

The discovery of anaerobic ammonium oxidation (anammox) changed the concept that ammonium was only oxidized under aerobic condition, which has been widely accepted. Anammox is the process that anammox bacteria oxidize ammonium using nitrite as electron acceptor under anaerobic condition. The application of anammox for treating wastewater can considerably reduce the energy consumption of wastewater treatment. However, the enrichment of anammox in wastewater treatment system would take a long time. This limited the application of anammox in wastewater treatment. The discovery of quorum sensing overturned the traditional microbiology view that microorganism existed independently, and opened a new chapter in microorganism social behavior. It will provide a new theory basis for regulating microbial community.. The quorum sensing of anammox bacteria will be studied, and the signaling molecules will be identified in this study. Meanwhile, the effect of environmental conditions on the production and degradation of signaling molecules will also be investigated. The role the signaling molecules play in anammox growth metabolism will be illuminated. And the function of signaling molecules in extracellular polymeric substances synthesis will be discussed. Finally, a new method of accumulating anammox bacteria in wastewater treatment system will be developed based on understanding quorum sensing. The expected results would guide the regulation of anammox bacteria community in wastewater treatment system. Meanwhile, this study has an positive role in giving a assistant interpretation for the internal mechanism of the anammox hotspots in nature.

厌氧氨氧化反应的发现改变了人们对氨只能在有氧条件下被氧化的认识，厌氧氨氧化是厌氧氨氧化菌在厌氧条件下以亚硝酸盐为电子受体氧化氨氮生成氮气。厌氧氨氧化应用于污水处理可大幅降低污水处理能耗，但厌氧氨氧化菌的富集培养慢限制了其应用。近年来群体感应现象的发现颠覆了“微生物作为独行者存在”的传统微生物学观点，开启了微生物社会行为学的新篇章，可为微生物菌群调控提供新的理论基础。. 本项目将深入研究厌氧氨氧化菌群体感应，鉴定群体感应信号分子，考察环境条件对信号分子生成与降解的影响规律；阐明信号分子对厌氧氨氧化菌生长代谢的作用机制，探讨信号分子对厌氧氨氧化菌胞外聚合物合成的作用，最后基于群体感应建立污水处理系统厌氧氨氧化菌快速富集方法。本项目预期成果在指导污水处理系统厌氧氨氧化菌群调控的同时，还有望辅助解释自然界厌氧氨氧化热区分布规律。

厌氧氨氧化应用于污水处理可大幅降低污水处理能耗，但厌氧氨氧化菌生长慢限制了其应用。近年来群体感应现象的发现，开启了微生物社会行为学的新篇章，为微生物菌群调控提供新的理论基础。本项目研究典型信号分子C6-HSL和C8-HSL对厌氧氨氧化菌生长与厌氧氨氧化菌功能基因hzsA表达的影响，探讨了AHLs 诱导厌氧氨氧化菌基因表达的机理模型；基于形成生物膜提高信号分子浓度,构建了A/O生物膜系统实现短程反硝化厌氧氨氧化脱氮，同时研究了FNA与FA处理污泥实现短程硝化为厌氧氨氧化菌提供底物亚硝酸盐的方法。. 研究结果表明投加外源信号分子C6-HSL和C8-HSL可增加厌氧氨氧化菌的氮去除速率，但对厌氧氨氧化菌生长速率影响不大；同时可提高厌氧氨氧化功能基因hzsA的表达量，这可能是信号分子促进氮去除速率的原因；基于生物膜可提高信号分子浓度促进厌氧氨氧化菌生长繁殖的规律，构建的A/O生物膜系统，在缺氧区实现了稳定的短程反硝化厌氧氨氧化，在进水C/N为2.6的情况下实现了TN去除率高达80%，且70%的氮气是由厌氧氨氧化产生的，相关成果发表在Environ. Sci. Technol.（2017）上。. 研究成果对于理解信号分子对厌氧氨氧化菌生长代谢的影响极其作用机制，推动厌氧氨氧化生物脱氮在低C/N比城市污水处理厂的应用等方面具有重要意义。