Details

Autor(en) / Beteiligte

• Ettwig, Katharina F.
• Zhu, Baoli
• Speth, Daan
• Keltjens, Jan T.
• Jetten, Mike S. M.
• Kartal, Boran

Titel

Archaea catalyze iron-dependent anaerobic oxidation of methane

Ist Teil von

• Proceedings of the National Academy of Sciences - PNAS, 2016-11, Vol.113 (45), p.12792-12796

Ort / Verlag

United States: National Academy of Sciences

Erscheinungsjahr

2016

Quelle

Free E-Journal (出版社公開部分のみ）

Beschreibungen/Notizen

• Anaerobic oxidation of methane (AOM) is crucial for controlling the emission of this potent greenhouse gas to the atmosphere. Nitrite-, nitrate-, and sulfate-dependent methane oxidation is well-documented, but AOM coupled to the reduction of oxidized metals has so far been demonstrated only in environmental samples. Here, using a freshwater enrichment culture, we show that archaea of the order Methanosarcinales, related to “Candidatus Methanoperedens nitroreducens,” couple the reduction of environmentally relevant forms of Fe3+ and Mn4+ to the oxidation of methane. We obtained an enrichment culture of these archaea under anaerobic, nitrate-reducing conditions with a continuous supply of methane. Via batch incubations using [13C]methane, we demonstrated that soluble ferric iron (Fe3+, as Fe-citrate) and nanoparticulate forms of Fe3+ and Mn4+ supported methane-oxidizing activity. CO₂ and ferrous iron (Fe2+) were produced in stoichiometric amounts. Our study connects the previous finding of iron-dependent AOM to microorganisms detected in numerous habitats worldwide. Consequently, it enables a better understanding of the interaction between the biogeochemical cycles of iron and methane.