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Carbon isotope effects associated with aceticlastic methanogenesis.
J T Gelwicks1, J B Risatti, J M Hayes
1Departments of Chemistry and Geological Sciences, Indiana University, Bloomington 47405, USA.
Applied and Environmental Microbiology
|February 1, 1994
Summary
Researchers studied carbon isotope effects in methane production from acetate by Methanosarcina barkeri and lake sediment microbes. Findings help model carbon flow and interpret methane
Area of Science:
- Microbiology
- Biogeochemistry
- Isotope Geochemistry
Background:
- Methane production from acetate is a key microbial process in anoxic environments.
- Carbon isotope fractionation provides insights into microbial metabolic pathways.
Purpose of the Study:
- Quantify carbon isotope effects for acetate-to-methane conversion in specific methanogens and natural communities.
- Develop a model to understand carbon flow and isotopic signatures in methane production.
Main Methods:
- Incubation of Methanosarcina barkeri with labeled acetate.
- Analysis of carbon isotope composition (13C) in methane and acetate.
- Sampling and isotopic analysis of methanogenic archaea in lake sediment.
Main Results:
- Measured a significant 13C isotope effect of -21.3% for M. barkeri and -19.2% for lake sediment archaea.
- Observed similar isotope effects for methyl and carboxyl carbons, supporting carbon monoxide dehydrogenase involvement.
- Successfully modeled carbon flow to methane using observed isotope effects.
Conclusions:
- Carbon isotope effects in methane synthesis are quantifiable and predictable.
- The developed model accurately accounts for methane carbon isotope compositions in lake sediments.
- Findings aid in interpreting methane cycling and carbon sources in various ecosystems.