反硝化型甲烷厌氧氧化的研究进展

Research progress in denitrifying anaerobic methane oxidation

反硝化型甲烷厌氧氧化（denitrifying anaerobic methane oxidation,DAMO）即甲烷厌氧氧化耦合反硝化,是指在厌氧条件下以甲烷作为电子供体,NO2-/NO3-作为电子受体的反硝化过程。甲烷是一种温室气体,其引起的温室效应是等物质量CO2的20～30倍。DAMO过程利用甲烷代替常规碳源进行脱氮,有利于减少温室效应,并改善氮循环。研究发现,Candidatus Methylomirabilis oxyfera细菌和Candidatus Methanoperedens nitroreducens古菌是参与DAMO过程的2类主要功能微生物,前者通过内部好氧机制耦合亚硝酸盐还原与甲烷的厌氧氧化,后者则通过逆向产甲烷途径耦合硝酸盐还原与甲烷的厌氧氧化。本文详细阐述了M.oxyfera细菌和M.nitroreducens古菌细胞内代谢途径,着重总结了甲烷、NO2-/NO3-、反应器构型、温度等因素对DAMO性能的影响。并对DAMO实际应用方面的研究现状做了调研。在DAMO功能微生物作用机制、快速富集及影响因素的进一步深入研究的基础上,推进DAMO污水脱氮工艺的应用是未来的主要研究热点和发展方向。

Denitrifying anaerobic methane oxidation（ DAMO） is a novel denitrification process with methane as the electron donor and NO3-/ NO2-as the electron acceptor under anaerobic condition. As a greenhouse gas,CH4 has 20- 30 times greater global warming potential than CO2.CH4,instead of conventional carbon source,is used for denitrification in the process of DAMO,which is beneficial for reducing global warming effect and improving nitrogen cycle. It has been found that Candidatus Methylomirabilis oxyfera（ belonging to bacteria） and Candidatus Methanoperedens nitroreducens（ archaea） are the two main microbial communities participating in DAMO process. The former conducts NO2--DAMO process via ＂intraaerobic pathway＂while the other uses ＂reverse methanogenesis pathway＂to couple NO3-reduction with methane anaerobic oxidation. This paper elaborated the intracellular metabolic pathway of M. oxyfera and M. nitroreducens,and summarized the influence factors of DAMO process in detail,including substrate（ CH4 and NO2-/ NO3-） concentration,reactor configuration and temperature,etc. Meanwhile,the current status of DAMO application on nitrogen removal was also investigated. With further exploration of the mechanisms,enrichment and influence factors of microbial communities,the propulsion of DAMO industrial application would be the frontier in the future.