厌氧甲烷氧化微生物物质代谢与能量代谢研究进展

Advances in catabolism and energy metabolism of anaerobic methane-oxidizing microorganisms

摘要:

甲烷既是一种温室气体，也是一种潜在的能源物质，其源与汇的平衡对地球化学循环及工程应用均有重要意义。厌氧甲烷氧化(anaerobic oxidation of methane，AOM)过程是深海、湿地和农田等自然生境中重要的甲烷汇，在缓解温室气体排放方面发挥了巨大作用。AOM微生物的中枢代谢机制及其能量转化途径则是介导厌氧甲烷氧化耦合其他物质还原的关键所在。因此，本文从电子受体多样性的视角，主要分析了硫酸盐型，硝酸盐/亚硝酸盐型，金属还原型厌氧甲烷氧化微生物的生理生化过程及环境分布，并对近些年发现的新型厌氧甲烷氧化进行了梳理；重点总结了厌氧甲烷氧化微生物细胞内电子传递路径以及胞外电子传递方式；根据厌氧甲烷氧化微生物环境分布及反应特征，就其生态学意义及在污染治理与能源回收方面的潜在应用价值进行了展望。本综述以期深化对厌氧甲烷氧化过程的微生物学认知，并为其潜在的工程应用方向提供新的思路。

关键词:厌氧甲烷氧化;电子受体;微生物分布;物质代谢;能量代谢

Abstract:

Methane is not only a greenhouse gas but also a potential energy substance. The balance of methane source and sink is of great significance to geochemical cycle and engineering application. Anaerobic oxidation of methane (AOM) is an important methane sink in natural habitats such as deep sea, wetland, and farmland, which plays a role in mitigating greenhouse gas emissions. The central metabolic mechanism and energy conversion pathways of methane-oxidizing microorganisms are the key to AOM coupled with the reduction of other substances. Therefore, from the perspective of electron acceptor diversity, we analyzed the physiological and biochemical processes and environmental distribution of sulfate-, nitrate/nitrite-, and metal-reducing anaerobic methane-oxidizing microorganisms, and reviewed the new anaerobic methane-oxidizing microorganisms discovered in recent years. Further, we summarized the intracellular and extracellular electron transport pathways of anaerobic methane-oxidizing microorganisms. According to the environmental distribution and reaction characteristics, we prospected the ecological significance and potential application value of anaerobic methane-oxidizing microorganisms in pollution control and energy recovery. Through the review, we aim to deepen the understanding of the microbial processes of AOM and shed light on its potential engineering application.

Key words:anaerobic oxidation of methane;electron acceptor;microorganism distribution;catabolism;energy metabolism