Enzymatic versus nonenzymatic mechanisms for Fe(III) reduction in aquatic sediments

Journal Article · Sat Jun 01 00:00:00 EDT 1991 · Environmental Science and Technology; (United States)

DOI:https://doi.org/10.1021/es00018a007· OSTI ID:5118160

Lovely, D R; Phillips, E J.P.; Lonergan, D J ^[1]

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1. Geological Survey, Reston, VA (United States)

The potential for nonenzymatic reduction of Fe(III) either by organic compounds or by the development of a low redox potential during microbial metabolism was compared with direct, enzymatic Fe(III) reduction by Fe(III)-reducing microorganisms. At circumneutral pH, very few organic compounds nonenzymatically reduced Fe(III). In contrast, in the presence of the appropriate Fe(III)-reducing microorganisms, most of the organic compounds examined could be completely oxidized to carbon dioxide with the reduction of Fe(III). Even for those organic compounds that could nonenzymatically reduce Fe(III), microbial Fe(III) reduction was much more extensive. The development of a low redox potential during microbial fermentation did not result in nonenzymatic Fe(III) reduction. Model organic compounds were readily oxidized in Fe(III)-reducing aquifer sediments, but not in sterilized sediments. These results suggest that microorganisms enzymatically catalyze most of the Fe(III) reduction in the Fe(III) reduction zone of aquatic sediments and aquifers.

• OSTI ID: 5118160
• Journal Information: Environmental Science and Technology; (United States), Vol. 25:6; ISSN 0013-936X
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AQUATIC ECOSYSTEMS
BIOCHEMICAL REACTION KINETICS
IRON
REDUCTION
CARBON 14 COMPOUNDS
CARBON DIOXIDE
CHEMICAL REACTION KINETICS
CLOSTRIDIUM
CYSTEINE
ENZYME ACTIVITY
ESCHERICHIA COLI
FRUCTOSE
GAS CHROMATOGRAPHY
GLUCOSE
IRON OXIDES
METABOLIC ACTIVATION
MICROORGANISMS
ORGANIC MATTER
PH VALUE
QUANTITATIVE CHEMICAL ANALYSIS
SEDIMENTS
ALDEHYDES
AMINO ACIDS
BACTERIA
CARBOHYDRATES
CARBON COMPOUNDS
CARBON OXIDES
CARBOXYLIC ACIDS
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL REACTIONS
CHROMATOGRAPHY
ECOSYSTEMS
ELEMENTS
HEXOSES
IRON COMPOUNDS
KETONES
KINETICS
LABELLED COMPOUNDS
MATTER
METALS
MONOSACCHARIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
SACCHARIDES
SEPARATION PROCESSES
THIOLS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
540320* - Environment
Aquatic- Chemicals Monitoring & Transport- (1990-)