@article {605,
	title = {Humics as an electron donor for anaerobic respiration.},
	journal = {Environ Microbiol},
	volume = {1},
	year = {1999},
	month = {1999 Feb},
	pages = {89-98},
	abstract = {The possibility that microorganisms might use reduced humic substances (humics) as an electron donor for the reduction of electron acceptors with a more positive redox potential was investigated. All of the Fe(III)- and humics-reducing microorganisms evaluated were capable of oxidizing reduced humics and/or the reduced humics analogue anthrahydroquinone-2,6,-disulphonate (AHODS), with nitrate and/or fumarate as the electron acceptor. These included Geobacter metallireducens, Geobacter sulphurreducens, Geothrix fermentans, Shewanella alga, Wolinella succinogenes and {\textquoteright}S. barnesii{\textquoteright}. Several of the humics-oxidizing microorganisms grew in medium with AHQDS as the sole electron donor and fumarate as the electron acceptor. Even though it does not reduce Fe(III) or humics, Paracoccus denitrificans could use AHQDS and reduced humics as electron donors for denitrification. However, another denitrifier, Pseudomonas denitrificans, could not. AHODS could also serve as an electron donor for selenate and arsenate reduction by W. succinogenes. Electron spin resonance studies demonstrated that humics oxidation was associated with the oxidation of hydroquinone moieties in the humics. Studies with G. metallireducens and W. succinogenes demonstrated that the anthraquinone-2,6-disulphonate (AQDS)/AHQDS redox couple mediated an interspecies electron transfer between the two organisms. These results suggest that, as microbially reduced humics enter less reduced zones of soils and sediments, the reduced humics may serve as electron donors for microbial reduction of several environmentally significant electron acceptors.},
	keywords = {Aerobiosis, Anaerobiosis, Anthraquinones, Arsenates, Bacteria, Electron Transport, Fumarates, Humic Substances, Selenium Compounds, Tumor Cells, Cultured},
	issn = {1462-2912},
	author = {Lovley, D R and Fraga, J L and Coates, J D and Blunt-Harris, E L}
}
@article {619,
	title = {Microbial communities associated with anaerobic benzene degradation in a petroleum-contaminated aquifer.},
	journal = {Appl Environ Microbiol},
	volume = {65},
	year = {1999},
	month = {1999 Jul},
	pages = {3056-63},
	abstract = {Microbial community composition associated with benzene oxidation under in situ Fe(III)-reducing conditions in a petroleum-contaminated aquifer located in Bemidji, Minn., was investigated. Community structure associated with benzene degradation was compared to sediment communities that did not anaerobically oxidize benzene which were obtained from two adjacent Fe(III)-reducing sites and from methanogenic and uncontaminated zones. Denaturing gradient gel electrophoresis of 16S rDNA sequences amplified with bacterial or Geobacteraceae-specific primers indicated significant differences in the composition of the microbial communities at the different sites. Most notable was a selective enrichment of microorganisms in the Geobacter cluster seen in the benzene-degrading sediments. This finding was in accordance with phospholipid fatty acid analysis and most-probable-number-PCR enumeration, which indicated that members of the family Geobacteraceae were more numerous in these sediments. A benzene-oxidizing Fe(III)-reducing enrichment culture was established from benzene-degrading sediments and contained an organism closely related to the uncultivated Geobacter spp. This genus contains the only known organisms that can oxidize aromatic compounds with the reduction of Fe(III). Sequences closely related to the Fe(III) reducer Geothrix fermentans and the aerobe Variovorax paradoxus were also amplified from the benzene-degrading enrichment and were present in the benzene-degrading sediments. However, neither G. fermentans nor V. paradoxus is known to oxidize aromatic compounds with the reduction of Fe(III), and there was no apparent enrichment of these organisms in the benzene-degrading sediments. These results suggest that Geobacter spp. play an important role in the anaerobic oxidation of benzene in the Bemidji aquifer and that molecular community analysis may be a powerful tool for predicting a site{\textquoteright}s capacity for anaerobic benzene degradation.},
	keywords = {Anaerobiosis, Benzene, Biodegradation, Environmental, Culture Media, DNA, Bacterial, DNA, Ribosomal, Fresh Water, Geologic Sediments, Gram-Negative Anaerobic Bacteria, Molecular Sequence Data, Oxidation-Reduction, Petroleum, Phylogeny, Polymerase Chain Reaction, RNA, Ribosomal, 16S, Sequence Analysis, DNA, Water Pollutants},
	issn = {0099-2240},
	author = {Rooney-Varga, J N and Anderson, R T and Fraga, J L and Ringelberg, D and Lovley, D R}
}
