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Carbon isotope effects associated with aceticlastic methanogenesisThe carbon isotope effects associated with synthesis of methane from acetate have been determined for Methanosarcina barkeri 227 and for methanogenic archaea in sediments of Wintergreen Lake, Michigan. At 37 degrees C, the 13C isotope effect for the reaction acetate (methyl carbon) --> methane, as measured in replicate experiments with M. barkeri, was - 21.3% +/- 0.3%. The isotope effect at the carboxyl portion of acetate was essentially equal, indicating participation of both positions in the rate-determining step, as expected for reactions catalyzed by carbon monoxide dehydrogenase. A similar isotope effect, - 19.2% +/- 0.3% was found for this reaction in the natural community (temperature = 20 degrees C). Given these observations, it has been possible to model the flow of carbon to methane within lake sediment communities and to account for carbon isotope compositions of evolving methane. Extension of the model allows interpretation of seasonal fluctuations in 13C contents of methane in other systems.
Document ID
20040112249
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Gelwicks, J. T.
(Indiana University Bloomington 47405, United States)
Risatti, J. B.
Hayes, J. M.
Date Acquired
August 21, 2013
Publication Date
February 1, 1994
Publication Information
Publication: Applied and environmental microbiology
Volume: 60
Issue: 2
ISSN: 0099-2240
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: NGR15003-118
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Exobiology
Non-NASA Center

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