C-isotopic fractionation during methylotrophic methanogenesis
Conference
·
· AAPG Bulletin
OSTI ID:6567137
- AGSO, Canberra (Australia)
- Univ. of Tasmania, Hobart (Australia)
Methanogenesis from non-competitive substrates such as trimethylamine (TMA) may be quantitatively important in global methane budgets. This is because choline, glycine betaine and related compounds, precursors of TMA, are produced abundantly and ubiquitously by microbes, particularly those from marine and saline lacustrine environments. These substrates may source methane supersaturating oceanic seawater, possibly formed in anaerobic microhabitats (e.g. zooplankton guts and within particulates) and indicated by carbon isotopic analysis of abundant methanogen-derived hydrocarbons (e.g. 2, 6, 10, 15, 19-pentamethyleicosane, PME) found in recent and ancient marine sediments. In order to elaborate on these observations using cultured organisms we measured isotopic fractionation for methane and lipids formed by methanogens using trimethylamine as their carbon source. Methanosarcina barkerii showed fractionation factors ([epsilon]) of 50.2[per thousand] for conversion of TMA to methane and 20.2[per thousand] for TMA-biomass. Moreover PME and phytanyl chains of K barkerii ether lipid were depleted by as much as 18[per thousand] compared to biomass. For the Antarctic methanogen Methanococcoides burtonii we measured even greater e values of 71[per thousand] (TMA-CH[sub 4]), 49.6[per thousand] (TMA- biomass) and 79.9[per thousand] (TMA-phytanyl ether). It should be noted that these E values represent maximum or near maximum values for non-limiting substrate concentrations and are significantly higher than those reported for aceticlastic methanogenesis (approx 21%.) or reduction of carbon dioxide (32 to 46[per thousand]). Methylotrophic methanogenesis may be the source of extremely [sup 13]C-depleted methane in certain gas accumulations.
- OSTI ID:
- 6567137
- Report Number(s):
- CONF-960527--
- Conference Information:
- Journal Name: AAPG Bulletin Journal Volume: 5
- Country of Publication:
- United States
- Language:
- English
Similar Records
C-isotopic fractionation during methylotrophic methanogenesis
Isolation and characterization of a methylotrophic marine methanogen, Methanococcoides methylutens gen. nov. , sp
Significance of ether lipids derived from methanogens in sediments from modern and ancient basins
Conference
·
Mon Dec 30 23:00:00 EST 1996
·
OSTI ID:425890
Isolation and characterization of a methylotrophic marine methanogen, Methanococcoides methylutens gen. nov. , sp
Conference
·
Mon Jan 31 23:00:00 EST 1983
· Appl. Environ. Microbiol.; (United States)
·
OSTI ID:5495449
Significance of ether lipids derived from methanogens in sediments from modern and ancient basins
Conference
·
Mon Dec 30 23:00:00 EST 1996
·
OSTI ID:425853