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Carbon Isotope Fractionations Associated with Methanotrophic Growth with the Soluble and Particulate Methane MonooxygenasesGrowth experiments with the RuMP-type methanotroph, Methylococcus capsulatus (Bath), have demonstrated that biomass and lipid biomarkers are significantly depleted in C-13 compared to the substrate methane and that the extent of fractionation is dependent on whether cells express the soluble (s) or particulate (p) methane monooxygenase (MMO). The presence or absence of the characteristic sMMO subunits was monitored using SDS-polyacrylamide gels. In M. capsulatus grown with no Cu supplementation, the characteristic sMMO subunits were observed in the soluble fraction throughout the entire growth period and biomass was depleted in C-13 by approximately 14,700 relative to substrate methane. In cells grown with 5uM Cu, no sMMO bands were observed and a greater fractionation of approximately 27,700 in resultant biomass was obtained. Methanol growth experiments with M. capsulatus and with a RuMP methylotroph, Methylophilus methylotrophus, in which biomass measurements yielded depletions in C-13 of 9 and 5%(sub o), respectively, suggest that oxidation of methane is the major fractionation step. Growth of M. capsulatus at a low level of oxygen, approximately 0.5%, had no significant effect on carbon isotope fractionation by either sMMO or pMMO. These observations are significant for identification of molecular biomarkers; and methanotrophic contributions to carbon isotope composition in natural environments.
Document ID
20020032684
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Jahnke, Linda L.
Summons, Roger E.
Chang, Sherwood
Date Acquired
August 20, 2013
Publication Date
January 1, 1996
Subject Category
Inorganic, Organic And Physical Chemistry
Meeting Information
Meeting: 96th American Chemical Society Meeting
Location: New Orleans, LA
Country: United States
Start Date: May 20, 1996
End Date: May 23, 1996
Sponsors: American Chemical Society
Funding Number(s)
PROJECT: RTOP 185-52-32
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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