Effect of sulfate on carbon and electron flow during microbial methanogenesis in freshwater sediments
The effect of sulfate on methane production in Lake Mendota sediments was investigated to clarify the mechanism of sulfate inhibition of methanogenesis. Methanogenesis was shown to be inhibited by the addition of as little as 0.2 mM sulfate. Sulfate inhibition was reversed by the addition of either H/sub 2/ or acetate. Methane evolved when inhibition was reversed by H/sub 2/ additions was derived from /sup 11/CO/sub 2/. Conversely, when acetate was added to overcome sulfate inhibition, the evolved methane was derived from (2-/sup 14/C) acetate. A competition for available H/sub 2/ and acetate was proposed as the mechanism by which sulfate inhibited methanogenesis. Acetate was shown to be metabolized even in the absence of methanogenic activity. In the presence of sulfate, the methyl position of acetate was converted to CO/sub 2/. The addition of sulfate to sediments did not result in the accumulation of significant amounts of sulfide in the pore water. Sulfate additions did not inhibit methanogenesis unless greater than 100 ..mu..g of free sulfide per ml was present in the pore water. These results indicate that carbon and electron flow are altered when sulfate is added to sediments. Sulfate-reducing organisms appear to assume the role of methanogenic bacteria in sulfate-containing sediments by utilizing methanogenic precursors.
- Research Organization:
- Univ. of Wisconsin, Madison
- OSTI ID:
- 6551762
- Journal Information:
- Appl. Environ. Microbiol.; (United States), Vol. 33:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
METHANE
BIOSYNTHESIS
BACTERIA
ELECTRON TRANSFER
FRESH WATER
INHIBITION
MATERIAL BALANCE
SEDIMENTS
SULFATES
ALKANES
CRYOGENIC FLUIDS
FLUIDS
HYDROCARBONS
HYDROGEN COMPOUNDS
MICROORGANISMS
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
SULFUR COMPOUNDS
SYNTHESIS
WATER
090122* - Hydrocarbon Fuels- Preparation from Wastes or Biomass- (1976-1989)
550700 - Microbiology