Archaea catalyze iron-dependent anaerobic oxidation of methane
Abstract
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 Fe^(3+) and Mn^(4+) 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 [^(13)C]methane, we demonstrated that soluble ferric iron (Fe^(3+), as Fe-citrate) and nanoparticulate forms of Fe^(3+) and Mn^(4+) supported methane-oxidizing activity. CO_2 and ferrous iron (Fe^(2+)) 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.
Additional Information
© 2016 National Academy of Sciences. Edited by Donald E. Canfield, Institute of Biology and Nordic Center for Earth Evolution, University of Southern Denmark, Odense M, Denmark, and approved September 16, 2016 (received for review June 13, 2016). Published online before print October 24, 2016. We thank Francisca A. Luesken for starting and initially maintaining the AAA enrichment culture. K.F.E. was supported by a VENI grant from The Netherlands Organization for Scientific Research (863.13.007), B.Z. by the joint program of the Chinese Academy of Science/Royal Dutch Academy of Science (09PhD02), D.S. by the BE-Basic Foundation (fp07.002), M.S.M.J. by the European Research Council (ERC 339880) and the Spinoza Prize, and B.K. by a VENI grant from The Netherlands Organization for Scientific Research (863.11.003) and the European Research Council (ERC 640422). Author contributions: K.F.E., B.Z., M.S.M.J., and B.K. designed research; B.Z. and D.S. performed research; D.S. carried out sequencing and genome assembly; K.F.E., B.Z., J.T.K., M.S.M.J., and B.K. analyzed data; and K.F.E. and B.K. wrote the paper. The authors declare no conflict of interest. This article is a PNAS Direct Submission. Data deposition: The sequence reported in this paper has been deposited in the DDBJ/EMBL/GenBank database (metagenome accession no. LKCM01000000). This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1609534113/-/DCSupplemental.Attached Files
Published - PNAS-2016-Ettwig-12792-6.pdf
Supplemental Material - pnas.201609534SI.pdf
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Additional details
- PMCID
- PMC5111651
- Eprint ID
- 72844
- Resolver ID
- CaltechAUTHORS:20161215-103147761
- 863.13.007
- Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)
- Chinese Academy of Sciences
- 09PhD02
- Royal Dutch Academy of Science
- fp07.002
- BE-Basic Foundation
- 339880
- European Research Council (ERC)
- Spinoza Prize
- 863.11.003
- Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)
- 640422
- European Research Council (ERC)
- Created
-
2016-12-15Created from EPrint's datestamp field
- Updated
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2021-11-11Created from EPrint's last_modified field