Microbial reduction of soluble U(VI) to insoluble U(IV) represents a promising strategy for immobilizing uranium from contaminated groundwaters. This strategy may also be coupled with a soil washing technique for concentrating uranium from contaminated soils. We discovered that the U(VI)-reducing capacity of the Geobacter species that are naturally present in subsurface environments can be simply and effectively stimulated with the addition of an acetate solution to the groundwater. This precipitates uranium from the groundwater preventing its further mobility and concentrations uranium dispersed in a large volume of groundwater into a discrete zone for subsequent removal.
Geobacter species have been shown to play important roles in the bioremediation of groundwater contaminated with petroleum and landfill leachate. Soluble organic contaminants are oxidized to carbon dioxide with the reduction of iron oxides that are abundant in most subsurface environments. Molecular analysis of a diversity of contaminated subsurface environments in which oxidation of pollutants coupled to iron oxide reduction is important have consistently found that these environments are enriched in Geobacter species.
We have also found that the ability of Geobacter species to interact with electrodes can be exploited to stimulate bioremediation of a wide range of common contaminants. Graphite electrodes serving as electron acceptors can greatly stimulate the degradation hydrocarbon contaminants. The graphite adsorbs hydrocarbons from the surrounding environment thus concentrating the contaminants, the degradative microorganisms, and an effective electron acceptor in the same location. Alternatively, electrodes can serve as an electron donor to promote the reductive dechlorination of chlorinated solvents and reductive precipitation of uranium from contaminated water.
(click each for a larger image)
|Overall view of the Rifle site||
Injection gallery and shed
Flowmeters connected to injection manifold and injection wells
Site layout looking downgadient
Kenneth H. Williams, Philip E. Long, James A. Davis, Michael J. Wilkins, A. Lucie N'Guessan, Carl I. Steefel, Li Yang, Darrell Newcomer, Frank A. Spane, Lee J. Kerkhof, Lora McGuinness, Richard Dayvault & Derek R. Lovley (2011): Acetate Availability and its Influence on Sustainable Bioremediation of Uranium-Contaminated Groundwater, Geomicrobiology Journal, 28:5-6, 519-539
Tian Zhang, Sarah M. Gannon, Kelly P. Nevin, Ashley E. Franks, and Derek R. Lovley 2010. Stimulating the anaerobic degradation of aromatic hydrocarbons in contaminated sediments by providing an electrode as the electron acceptor. Environ Microbiol 12(4):1011-1020.
Kenneth H. Williams, Kelly P. Nevin, Ashley E. Franks, Andreas Englert, Philip E. Long, and Derek R. Lovley. 2010. Electrode-based approach for monitoring in situ microbial activity during subsurface bioremediation. Environ Sci Technol 44(1):47-54.
Sarah M. Strycharz, Sarah M. Gannon, Amber R. Boles, Ashley E. Franks, Kelly P. Nevin and Derek R. Lovley. 2010. Reductive dechlorination of 2-chlorophenol by Anaeromyxobacter dehalogenans with an electrode serving as the electron donor. Environ Microbio Reports 2(2):289-294.
Lucie A. N’Guessan, Helen A. Vrionis, Charles T. Resch, Philip E. Long, and Derek R. Lovley. 2008. Sustained removal of uranium from contaminated groundwater following stimulation of dissimilatory metal reduction. Environ Sci Technol 42(8):2999-3004.
Sarah M. Strycharz, Trevor L. Woodard, Jessica P. Johnson, Kelly P. Nevin, Robert A. Sanford, Frank E. Löffler, and Derek R. Lovley. 2008. Graphite electrode as a sole electron donor for reductive dechlorination of tetrachlorethene by Geobacter lovleyi. Appl Environ Microbiol 74(19):5943-5947.
Dawn E. Holmes, Regina A. O’Neil, Helen A. Vrionis, Lucie A. N’Guessan, Irene Ortiz-Bernad, Maria J. Larrahondo, Lorrie A. Adams, Joy A. Ward, Julie S. Nicoll, Kelly P. Nevin, Milind A. Chavan, Jessica P. Johnson, Philip E. Long, and Derek R. Lovley. 2007. Subsurface clade of Geobacteraceae that predominates in a diversity of Fe(III)-reducing subsurface environments. ISME J 1(8):663-677.
Jessica E. Butler, Qiang He, Kelly P. Nevin, Zhili He, Jizhong Zhou, and Derek R. Lovley. 2007. Genomic and microarray analysis of aromatics degradation in Geobacter metallireducens and comparison to a Geobacter isolate from a contaminated field site. BMC Genomics 8
Kelvin B. Gregory, and Derek R. Lovley. 2005. Remediation and recovery of uranium from contaminated subsurface environments with electrodes. Environ Sci Technol 39(22):8943-8947.
Kelly P. Nevin, Kevin T. Finneran, and Derek R. Lovley. 2003. Microorganisms associated with uranium bioremediation in a high-salinity subsurface sediment. Appl Environ Microbiol 69(6):3672-3675.
Robert T. Anderson, Helen A. Vrionis, Irene Ortiz-Bernad, Charles T. Resch, Philip E. Long, Richard Dayvault, Ken Karp, Sam Marutzky, Donald R. Metzler, Aaron Peacock, David C. White, Mary Lowe, and Derek R. Lovley. 2003. Stimulating the in situ activity of Geobacter species to remove uranium from the groundwater of a uranium-contaminated aquifer. Appl Environ Microbiol 69(10):5884-5891.
Derek R. Lovley 2003. Cleaning up with genomics: Applying molecular biology to bioremediation. Nature Reviews Microbiology 1(1):36-44.
Kevin T. Finneran, Robert T. Anderson, Kelly P. Nevin, and Derek R. Lovley. 2002. Potential for bioremediation of uranium-contaminated aquifers with microbial U(VI) reduction. Soil and Sediment Contamination 11(3):339-357.
Dawn E. Holmes, Kevin T. Finneran, Regina A. O’Neil, and Derek R. Lovley. 2002. Enrichment of members of the family Geobacteraceae associated with stimulation of dissimilatory metal reduction in uranium-contaminated aquifer sediments. Appl Environ Microbiol 68(5):2300-2306.
Kevin T. Finneran, Meghan E. Housewright, and Derek R. Lovley. 2002. Multiple influences of nitrate on uranium solubility during bioremediation of uranium-contaminated subsurface sediments. Environ Microbiol 4(9):510-516.
Kevin T. Finneran, and Derek R. Lovley. 2001. Anaerobic degradation of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA). Environ Sci Technol 35(9):1785-1790.
Robert T. Anderson, and Derek R. Lovley. 1999. Naphthalene and benzene degradation under Fe(III)-reducing conditions in petroleum-contaminated aquifers. Bioremediation J 3(2):121-135.
Rooney-Varga, J.N., Robert T. Anderson, Jocelyn L. Fraga, David Ringelberg, and Derek R. Lovley. 1999. Microbial communities associated with anaerobic benzene degradation in a petroleum-contaminated aquifer. Appl Environ Microbiol 65(7):3056-3063.
Robert T. Anderson, Juliette N. Rooney-Varga, Catherine V. Gaw, and Derek R. Lovley. 1998. Anaerobic benzene oxidation in the Fe(III) reduction zone of petroleum-contaminated aquifers. Environ Sci Technol(32):1222-1229.
Jonathan M. Weiner, Terry S. Lauck, and Derek R. Lovley. 1998. Enhanced anaerobic benzene degradation with the addition of sulfate. Bioremediation J 2(3&4):159-173.
Jonathan M. Weiner, and Derek R. Lovley. 1998. Anaerobic benzene degradation in petroleum-contaminated aquifer sediments after inoculation with a benzene-oxidizing enrichment. Appl Environ Microbiol 64(2):775-778.
Paul M. Bradley, Francis H. Chapelle, and Derek R. Lovley. 1998. Humic acids as electron acceptors for anaerobic microbial oxidation of vinyl chloride and dichloroethene. Appl Environ Microbiol 64(8):3102-3105.
John D. Coates, Joan C. Woodward, J. Allen, P. Philp, and Derek R. Lovley. 1997. Anaerobic degradation of polycyclic aromatic hydrocarbons and alkanes in petroleum-contaminated marine harbor sediments. Appl Environ Microbiol 63(9):3589-3593.
Derek R. Lovley, Joan C. Woodward, and Francis H. Chapelle. 1996. Rapid anaerobic benzene oxidation with a variety of chelated Fe(III) forms. Appl Environ Microbiol 62(1):288-291.
Derek R. Lovley, Joan C. Woodward, and Francis H. Chapelle. 1994. Stimulated anoxic biodegradation of aromatic hydrocarbons using Fe(III) ligands. Nature 370(6485):128-131.
Elizabeth J.P. Phillips, Edward R. Landa, and Derek R. Lovley. 1995. Remediation of uranium contaminated soils with bicarbonate extraction and microbial U(VI) reduction. J Ind Microbiol 14:203-207.
Derek R. Lovley, and Elizabeth J.P. Phillips. 1992. Bioremediation of uranium contamination with enzymatic uranium reduction. Environ Sci Technol 26(11):2228-2234.
Derek R. Lovley, Elizabeth J.P. Phillips, Yuri A. Gorby, and Edward R. Landa. 1991. Microbial reduction of uranium. Nature 350(6317):413-416.
Derek R. Lovley, and Debra J. Lonergan. 1990. Anaerobic oxidation of toluene, phenol, and p-cresol by the dissimilatory iron-reducing organism GS-15. Appl Environ Microbiol 56(6):1858-1864.
Derek R. Lovley, Mary Jo Baedecker, Debra J. Lonergan, Isabella M. Cozzarelli, Elizabeth J.P. Phillips, and Donald I. Siegel. 1989. Oxidation of aromatic contaminants coupled to microbial iron reduction. Nature 339(6222):297-299.
Geobacter - Cleaning up toxic waste, The Pulse of the Planet, Jul. 21, 2010.
Geobacter - Cleaning up toxic waste, Insciences.org, Feb. 12, 2009.
Uranium Clean-up, MicrobeWorld Radio, Dec. 03, 2004
Electrifying Toxic Cleanup - Electrodes could stimulate removal of radioactive waste, Science News, Sept. 4, 2004.
Super Microbe Cleans Up Uranium, Genome News Network, Dec, 12, 2003.
Microbes that can mop up uranium, The Guardian (online), Oct. 16, 2003.
Microbes that can mop up uranium, The Guardian, Oct. 15, 2003.
Bugs boost Cold War Clean-up, Nature ScienceUpdate, Nature (online), Oct. 13, 2003.
Mining bacteria's appetite for toxic waste - Researchers try to clean nuclear sites with microbes, San Francisco Chronicle, July 14, 2003.