Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada.
Super-cutting-edge Grand and Advanced Research (SUGAR) Program, Institute for Extra-cutting-edge Science and Technology Avant-garde Research, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan.
ISME J. 2024 Jan 8;18(1). doi: 10.1093/ismejo/wrae041.
Methanotrophic bacteria mitigate emissions of the potent greenhouse gas methane (CH4) from a variety of anthropogenic and natural sources, including freshwater lakes, which are large sources of CH4 on a global scale. Despite a dependence on dioxygen (O2) for CH4 oxidation, abundant populations of putatively aerobic methanotrophs have been detected within microoxic and anoxic waters and sediments of lakes. Experimental work has demonstrated active aerobic methanotrophs under those conditions, but how they are able to persist and oxidize CH4 under O2 deficiency remains enigmatic. In this review, we discuss possible mechanisms that underpin the persistence and activity of aerobic methanotrophs under O2-limiting conditions in freshwater habitats, particularly lakes, summarize experimental evidence for microbial oxidation of CH4 by aerobic bacteria under low or no O2, and suggest future research directions to further explore the ecology and metabolism of aerobic methanotrophs in O2-limiting environments.
产甲烷菌可以减轻各种人为和自然来源的温室气体甲烷 (CH4) 的排放，包括淡水湖泊，它们是全球范围内 CH4 的重要来源。尽管产甲烷菌依赖于氧气 (O2) 来氧化 CH4，但在微氧和缺氧的湖泊水和沉积物中已经检测到了大量的疑似好氧产甲烷菌。实验工作已经证明了在这些条件下有氧产甲烷菌的活性，但它们如何在 O2 缺乏的情况下得以生存并氧化 CH4 仍然是个谜。在这篇综述中，我们讨论了支持淡水生境（特别是湖泊）中产甲烷菌在 O2 限制条件下生存和活性的可能机制，总结了有氧细菌在低氧或无氧条件下氧化 CH4 的实验证据，并提出了未来的研究方向，以进一步探索有氧产甲烷菌在 O2 限制环境中的生态学和代谢。
