Anaerobic Biodegradation of Long-Chain <i>n</i>-Alkanes under Sulfate-Reducing Conditions

Caldwell, Matthew E.; Garrett, Robert M.; Prince, Roger C.; Suflita, Joseph M.

doi:10.1021/es9801083

Cited by 127 publications

(66 citation statements)

References 37 publications

(47 reference statements)

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“…Strict anaerobic technique was used for all culture manipulations as well as for media and substrate preparations (Hungate, 1969;Balch et al, 1979). Sulfate was analyzed by ion chromatography as described by Caldwell et al (1998).…”

Section: Methodsmentioning

confidence: 99%

Anaerobic phenanthrene mineralization by a carboxylating sulfate-reducing bacterial enrichment

et al. 2007

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Information on the susceptibility of higher molecular weight polynuclear aromatic hydrocarbons to anaerobic biodegradation is relatively rare. We obtained a sulfate-reducing bacterial enrichment capable of phenanthrene metabolism from a hydrocarbon-contaminated marine sediment. Phenanthrene degradation was in stoichiometric agreement with the theoretically expected amount of sulfate reduction and inhibited by molybdate. Mineralization of 14 C-phenanthrene by the enrichment was confirmed by the recovery of the expected amount of 14 CO 2 . Stable isotope studies with protonated or deuterated phenanthrene resulted in the detection of the correspondingly labeled phenanthrene carboxylic acid by gas chromatography-mass spectrometry. Comparison of the metabolite profile with a synthesized standard confirmed that the parent molecule was carboxylated at the C-2 position. Incorporation of 13 C-bicarbonate into the carboxyl group implicated a direct carboxylation of phenanthrene as a likely key initial reaction. Denaturing gradient gel electrophoresis analysis of the enrichment showed only two major bands and 16S rRNA sequences obtained by cloning clustered with known hydrocarbon-degrading sulfate-reducing d-proteobacteria, indicating their possible involvement in the anaerobic oxidation of phenanthrene via carboxylation as the initial activation reaction.

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Section: Methodsmentioning

confidence: 99%

Anaerobic phenanthrene mineralization by a carboxylating sulfate-reducing bacterial enrichment

et al. 2007

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“…Work with microbial consortia in the field, in enrichment cultures, and in microcosms has illustrated that hydrocarbons such as toluene (171,358), alkylbenzenes including m-, o-, and p-xylene and trimethylbenzenes (39,111,235,481), benzene (90,312,521), naphthalene and phenanthrene (50,124,421,686), methylnaphthalene and tetralin (20,23), ϾC 6 n-alkanes (18,96,168,575), branched alkanes (72,73), and hydrocarbon mixtures (228) can be metabolized under anaerobic conditions. These reactions may take place under Fe(III)-reducing, denitrifying, and sulfate-reducing conditions, by anoxygenic photosynthetic bacteria, or in syntrophic consortia of proton-reducing and methanogenic bacteria.…”

Section: Anaerobic Hydrocarbon Metabolismmentioning

confidence: 99%

Recent Advances in Petroleum Microbiology

Hamme¹,

Singh

Ward

2003

Microbiol Mol Biol Rev

1,193

640

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Recent advances in molecular biology have extended our understanding of the metabolic processes related to microbial transformation of petroleum hydrocarbons. The physiological responses of microorganisms to the presence of hydrocarbons, including cell surface alterations and adaptive mechanisms for uptake and efflux of these substrates, have been characterized. New molecular techniques have enhanced our ability to investigate the dynamics of microbial communities in petroleum-impacted ecosystems. By establishing conditions which maximize rates and extents of microbial growth, hydrocarbon access, and transformation, highly accelerated and bioreactor-based petroleum waste degradation processes have been implemented. Biofilters capable of removing and biodegrading volatile petroleum contaminants in air streams with short substrate-microbe contact times (<60 s) are being used effectively. Microbes are being injected into partially spent petroleum reservoirs to enhance oil recovery. However, these microbial processes have not exhibited consistent and effective performance, primarily because of our inability to control conditions in the subsurface environment. Microbes may be exploited to break stable oilfield emulsions to produce pipeline quality oil. There is interest in replacing physical oil desulfurization processes with biodesulfurization methods through promotion of selective sulfur removal without degradation of associated carbon moieties. However, since microbes require an environment containing some water, a two-phase oil-water system must be established to optimize contact between the microbes and the hydrocarbon, and such an emulsion is not easily created with viscous crude oil. This challenge may be circumvented by application of the technology to more refined gasoline and diesel substrates, where aqueous-hydrocarbon emulsions are more easily generated. Molecular approaches are being used to broaden the substrate specificity and increase the rates and extents of desulfurization. Bacterial processes are being commercialized for removal of H2S and sulfoxides from petrochemical waste streams. Microbes also have potential for use in removal of nitrogen from crude oil leading to reduced nitric oxide emissions provided that technical problems similar to those experienced in biodesulfurization can be solved. Enzymes are being exploited to produce added-value products from petroleum substrates, and bacterial biosensors are being used to analyze petroleum-contaminated environments

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“…n-Alkanes were anaerobically oxidized in pure cultures using sulfate (2,3,41,43) or nitrate (18) as the electron acceptor or in enrichment cultures with sulfate (16) or nitrate (13,39). Also, anaerobic conversion of long-chain n-alkanes to methane and CO 2 in associations of enriched bacteria and archaea was demonstrated (4,55).…”

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confidence: 99%

Anaerobic Initial Reaction of n -Alkanes in a Denitrifying Bacterium: Evidence for (1-Methylpentyl)succinate as Initial Product and for Involvement of an Organic Radical in n -Hexane Metabolism

et al. 2001

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A novel type of denitrifying bacterium (strain HxN1) with the capacity to oxidize n-alkanes anaerobically with nitrate as the electron acceptor to CO 2 formed (1-methylpentyl)succinate (MPS) during growth on n-hexane as the only organic substrate under strict exclusion of air. Identification of MPS by gas chromatography-mass spectrometry was based on comparison with a synthetic standard. MPS was not formed during anaerobic growth on n-hexanoate. Anaerobic growth with [1-13 C]n-hexane or d 14 -n-hexane led to a 1-methylpentyl side chain in MPS with one 13 C atom or 13 deuterium atoms, respectively. This indicates that the 1-methylpentyl side chain originates directly from n-hexane. Electron paramagnetic resonance spectroscopy revealed the presence of an organic radical in n-hexane-grown cells but not in n-hexanoate-grown cells. Results point at a mechanistic similarity between the anaerobic initial reaction of n-hexane and that of toluene, even though n-hexane is much less reactive; the described initial reaction of toluene in anaerobic bacteria is an addition to fumarate via a radical mechanism yielding benzylsuccinate. We conclude that n-hexane is activated at its second carbon atom by a radical reaction and presumably added to fumarate as a cosubstrate, yielding MPS as the first stable product. When 2,3-d 2 -fumarate was added to cultures growing on unlabeled n-hexane, 3-d 1 -MPS rather than 2,3-d 2 -MPS was detected, indicating loss of one deuterium atom by an as yet unknown mechanism.

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Anaerobic Biodegradation of Long-Chain n-Alkanes under Sulfate-Reducing Conditions

Cited by 127 publications

References 37 publications

Anaerobic phenanthrene mineralization by a carboxylating sulfate-reducing bacterial enrichment

Anaerobic phenanthrene mineralization by a carboxylating sulfate-reducing bacterial enrichment

Recent Advances in Petroleum Microbiology

Anaerobic Initial Reaction of n -Alkanes in a Denitrifying Bacterium: Evidence for (1-Methylpentyl)succinate as Initial Product and for Involvement of an Organic Radical in n -Hexane Metabolism

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