title: GeoChip-based analysis of functional microbial communities during the reoxidation of a bioreduced uranium-contaminated aquifer.
abstract: A pilot-scale system was established for in situ biostimulation of U(VI) reduction by ethanol addition at the US Department of Energy's (DOE's) Field Research Center (Oak Ridge, TN). After achieving U(VI) reduction, stability of the bioreduced U(IV) was evaluated under conditions of (i) resting (no ethanol injection), (ii) reoxidation by introducing dissolved oxygen (DO), and (iii) reinjection of ethanol. GeoChip, a functional gene array with probes for N, S and C cycling, metal resistance and contaminant degradation genes, was used for monitoring groundwater microbial communities. High diversity of all major functional groups was observed during all experimental phases. The microbial community was extremely responsive to ethanol, showing a substantial change in community structure with increased gene number and diversity after ethanol injections resumed. While gene numbers showed considerable variations, the relative abundance (i.e. percentage of each gene category) of most gene groups changed little. During the reoxidation period, U(VI) increased, suggesting reoxidation of reduced U(IV). However, when introduction of DO was stopped, U(VI) reduction resumed and returned to pre-reoxidation levels. These findings suggest that the community in this system can be stimulated and that the ability to reduce U(VI) can be maintained by the addition of electron donors. This biostimulation approach may potentially offer an effective means for the bioremediation of U(VI)-contaminated sites.
authors.affiliation: Institute for Environmental Genomics, University of Oklahoma, Norman, OK 73019, USA.
authors.forename: Joy D
authors.initials: JD
authors.lastname: Van Nostrand
authors.forename: Wei-Min
authors.initials: WM
authors.lastname: Wu
authors.forename: Liyou
authors.initials: L
authors.lastname: Wu
authors.forename: Ye
authors.initials: Y
authors.lastname: Deng
authors.forename: Jack
authors.initials: J
authors.lastname: Carley
authors.forename: Sue
authors.initials: S
authors.lastname: Carroll
authors.forename: Zhili
authors.initials: Z
authors.lastname: He
authors.forename: Baohua
authors.initials: B
authors.lastname: Gu
authors.forename: Jian
authors.initials: J
authors.lastname: Luo
authors.forename: Craig S
authors.initials: CS
authors.lastname: Criddle
authors.forename: David B
authors.initials: DB
authors.lastname: Watson
authors.forename: Philip M
authors.initials: PM
authors.lastname: Jardine
authors.forename: Terence L
authors.initials: TL
authors.lastname: Marsh
authors.forename: James M
authors.initials: JM
authors.lastname: Tiedje
authors.forename: Terry C
authors.initials: TC
authors.lastname: Hazen
authors.forename: Jizhong
authors.initials: J
authors.lastname: Zhou
mesh_terms: D001419:Bacteria / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D001673:Biodegradation, Environmental; D044822:Biodiversity; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D000431:Ethanol / Q000378:metabolism; D005798:Genes, Bacterial; D020411:Oligonucleotide Array Sequence Analysis; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D010802:Phylogeny; D014501:Uranium / Q000378:metabolism*; D014871:Water Microbiology; D014875:Water Pollutants, Radioactive / Q000378:metabolism
chemical_list: D004269:DNA, Bacterial; D014875:Water Pollutants, Radioactive; D000431:Ethanol; D014501:Uranium; D010100:Oxygen