Microbial communities in contaminated sediments, associated with bioremediation of uranium to submicromolar levels

Journal Article · Sat Mar 01 04:00:00 EST 2008 · Applied and Environmental Microbiology

DOI:https://doi.org/10.1128/AEM.02308-07· OSTI ID:986447

Cardenas, Erick ^[1]; Wu, Weimin ^[2]; Leigh, Mary Beth ^[1]; Carley, Jack M ^[3]; Carroll, Sue L ^[3]; Gentry, Terry ^[4]; Luo, Jian ^[5]; Watson, David B ^[3]; Gu, Baohua ^[3]; Ginder-Vogel, Matthew A ^[2]; Kitanidis, Peter K ^[2]; Jardine, Philip M ^[3]; Zhou, Jizhong ^[6]; Criddle, Craig ^[2]; Marsh, Terence ^[1]; Tiedje, James M ^[1]

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1. Michigan State University, East Lansing
2. Stanford University
3. ORNL
4. Texas A&M University
5. Georgia Institute of Technology
6. University of Oklahoma, Norman

Microbial enumeration, 16S rRNA gene clone libraries, and chemical analysis were used to evaluate the in situ biological reduction and immobilization of uranium(VI) in a long-term experiment (more than 2 years) conducted at a highly uranium-contaminated site (up to 60 mg/liter and 800 mg/kg solids) of the U.S. Department of Energy in Oak Ridge, TN. Bioreduction was achieved by conditioning groundwater above ground and then stimulating growth of denitrifying, Fe(III)-reducing, and sulfate-reducing bacteria in situ through weekly injection of ethanol into the subsurface. After nearly 2 years of intermittent injection of ethanol, aqueous U levels fell below the U.S. Environmental Protection Agency maximum contaminant level for drinking water and groundwater (<30 {micro}g/liter or 0.126 {micro}M). Sediment microbial communities from the treatment zone were compared with those from a control well without biostimulation. Most-probable-number estimations indicated that microorganisms implicated in bioremediation accumulated in the sediments of the treatment zone but were either absent or in very low numbers in an untreated control area. Organisms belonging to genera known to include U(VI) reducers were detected, including Desulfovibrio, Geobacter, Anaeromyxobacter, Desulfosporosinus, and Acidovorax spp. The predominant sulfate-reducing bacterial species were Desulfovibrio spp., while the iron reducers were represented by Ferribacterium spp. and Geothrix spp. Diversity-based clustering revealed differences between treated and untreated zones and also within samples of the treated area. Spatial differences in community structure within the treatment zone were likely related to the hydraulic pathway and to electron donor metabolism during biostimulation.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 986447
• Journal Information: Applied and Environmental Microbiology, Journal Name: Applied and Environmental Microbiology Journal Issue: 12 Vol. 74; ISSN 0099-2240
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
99 GENERAL AND MISCELLANEOUS
BINDING ENERGY
BIOREMEDIATION
CHEMICAL ANALYSIS
COMMUNITIES
DESULFOVIBRIO
DRINKING WATER
ELECTRONS
ETHANOL
GENES
HYDRAULICS
IRON
METABOLISM
MICROORGANISMS
SEDIMENTS
SULFATE-REDUCING BACTERIA
URANIUM
US EPA
VALENCE