GNS Science, Wairakei Research Centre, 114 Karetoto Rd, Taupō 3384, New Zealand.
School of Science, University of Waikato, Knighton Rd, Hamilton 3240, New Zealand.
FEMS Microbiol Ecol. 2019 Sep 1;95(9). doi: 10.1093/femsec/fiz125.
Methane is a potent greenhouse gas responsible for 20-30% of global climate change effects. The global methane budget is ∼500-600 Tg y-1, with the majority of methane produced via microbial processes, including anthropogenic-mediated sources such as ruminant animals, rice fields, sewage treatment facilities and landfills. It is estimated that microbially mediated methane oxidation (methanotrophy) consumes >50% of global methane flux each year. Methanotrophy research has primarily focused on mesophilic methanotrophic representatives and cooler environments such as freshwater, wetlands or marine habitats from which they are sourced. Nevertheless, geothermal emissions of geological methane, produced from magma and lithosphere degassing micro-seepages, mud volcanoes and other geological sources, contribute an estimated 33-75 Tg y-1 to the global methane budget. The aim of this review is to summarise current literature pertaining to the activity of thermophilic and thermotolerant methanotrophs, both proteobacterial (Methylocaldum, Methylococcus, Methylothermus) and verrucomicrobial (Methylacidiphilum). We assert, on the basis of recently reported molecular and geochemical data, that geothermal ecosystems host hitherto unidentified species capable of methane oxidation at higher temperatures.
甲烷是一种强效温室气体，对全球气候变化的影响约占 20-30%。全球甲烷预算约为 500-600 太克/年，其中大部分甲烷是通过微生物过程产生的，包括人为介导的来源，如反刍动物、稻田、污水处理厂和垃圾填埋场。据估计，微生物介导的甲烷氧化（甲烷营养）每年消耗全球甲烷通量的>50%。甲烷营养研究主要集中在中温甲烷营养代表物和较冷的环境中，如淡水、湿地或海洋栖息地，这些环境是甲烷的来源。然而，来自岩浆和岩石圈脱气微渗漏、泥火山和其他地质源的地质甲烷的地热排放，对全球甲烷预算的贡献估计为 33-75 太克/年。本综述的目的是总结有关嗜热和耐热甲烷营养菌的现有文献，包括变形菌（甲基球菌属、甲基杆菌属、甲基热敏菌属）和疣微菌（甲基嗜酸菌属）。根据最近报道的分子和地球化学数据，我们断言，地热生态系统中存在迄今尚未鉴定的物种，它们能够在更高的温度下进行甲烷氧化。
