Organic matter mineralization with reduction of ferric iron in anaerobic sediments

Journal Article · Tue Apr 01 00:00:00 EST 1986 · Appl. Environ. Microbiol.; (United States)

OSTI ID:5905392

Lovley, D R; Phillips, E J.P.

The potential for ferric iron reduction with fermentable substrates, fermentation products, and complex organic matter as electron donors was investigated with sediments from freshwater and brackish water sites in the Potomac River Estuary. In enrichments with glucose and hematite, iron reduction was a minor pathway for electron flow, and fermentation products accumulated. The substitution of amorphous ferric oxyhydroxide for hematite in glucose enrichments increased iron reduction 50-fold because the fermentation products could also be metabolized with concomitant iron reduction. Acetate, hydrogen, propionate, butyrate, ethanol, methanol, and trimethylamine stimulated the reduction of amorphous ferric oxyhydroxide in enrichments inoculated with sediments but not in uninoculated or heat-killed controls. The addition of ferric iron inhibited methane production in sediments. The degree of inhibition of methane production by various forms of ferric iron was related to the effectiveness of these ferric compounds as electron acceptors for the metabolism of acetate. The addition of acetate or hydrogen relieved the inhibition of methane production by ferric iron. The decrease of electron equivalents proceeding to methane in sediments supplemented with amorphous ferric oxyhydroxides was compensated for by a corresponding increase of electron equivalents in ferrous iron. These results indicate that iron reduction can out compete methanogenic food chains for sediment organic matter. Thus, when amorphous ferric oxyhydroxides are available in anaerobic sediments, the transfer of electrons from organic matter to ferric iron can be a major pathway for organic matter decomposition.

• Research Organization: Geological Survey, Reston, VA
• OSTI ID: 5905392
• Journal Information: Appl. Environ. Microbiol.; (United States), Vol. 51:4
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
54 ENVIRONMENTAL SCIENCES
IRON
BIODEGRADATION
METHANE
YIELDS
ORGANIC MATTER
MINERALIZATION
ELECTRON TRANSFER
FERMENTATION
GLUCOSE
METHANOGENIC BACTERIA
POTOMAC RIVER BASIN
SEDIMENTS
ALDEHYDES
ALKANES
BACTERIA
BIOCONVERSION
CARBOHYDRATES
CHEMICAL REACTIONS
DECOMPOSITION
ELEMENTS
HEXOSES
HYDROCARBONS
METALS
MICROORGANISMS
MONOSACCHARIDES
ORGANIC COMPOUNDS
SACCHARIDES
TRANSITION ELEMENTS
090122* - Hydrocarbon Fuels- Preparation from Wastes or Biomass- (1976-1989)
520200 - Environment
Aquatic- Chemicals Monitoring & Transport- (-1989)