Effect of methanogenic substrates on anaerobic oxidation of methane and sulfate reduction by an anaerobic methanotrophic enrichment.

Type
Article

Authors
Meulepas, Roel J W
Jagersma, Christian G
Khadem, Ahmad F
Stams, Alfons J M
Lens, Piet N L

Online Publication Date
2010-05-06

Print Publication Date
2010-07

Date
2010-05-06

Abstract
Anaerobic oxidation of methane (AOM) coupled to sulfate reduction (SR) is assumed to be a syntrophic process, in which methanotrophic archaea produce an interspecies electron carrier (IEC), which is subsequently utilized by sulfate-reducing bacteria. In this paper, six methanogenic substrates are tested as candidate-IECs by assessing their effect on AOM and SR by an anaerobic methanotrophic enrichment. The presence of acetate, formate or hydrogen enhanced SR, but did not inhibit AOM, nor did these substrates trigger methanogenesis. Carbon monoxide also enhanced SR but slightly inhibited AOM. Methanol did not enhance SR nor did it inhibit AOM, and methanethiol inhibited both SR and AOM completely. Subsequently, it was calculated at which candidate-IEC concentrations no more Gibbs free energy can be conserved from their production from methane at the applied conditions. These concentrations were at least 1,000 times lower can the final candidate-IEC concentration in the bulk liquid. Therefore, the tested candidate-IECs could not have been produced from methane during the incubations. Hence, acetate, formate, methanol, carbon monoxide, and hydrogen can be excluded as sole IEC in AOM coupled to SR. Methanethiol did inhibit AOM and can therefore not be excluded as IEC by this study.

Citation
Meulepas RJW, Jagersma CG, Khadem AF, Stams AJM, Lens PNL (2010) Effect of methanogenic substrates on anaerobic oxidation of methane and sulfate reduction by an anaerobic methanotrophic enrichment. Applied Microbiology and Biotechnology 87: 1499–1506. Available: http://dx.doi.org/10.1007/s00253-010-2597-0.

Acknowledgements
This work was part the Anaerobic Methane Oxidation for Sulfate Reduction project supported by the Dutch ministries of Economical affairs, Education, culture and science, and Environment and special planning as part their EET program and was cofunded by King Abdullah University of Science and Technology through the SOWACOR project.

Publisher
Springer Nature

Journal
Applied Microbiology and Biotechnology

DOI
10.1007/s00253-010-2597-0

PubMed ID
20445975

PubMed Central ID
PMC2892604

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