138 Matching Results

Search Results

Advanced search parameters have been applied.
in subjects: "Anaerobic Conditions"  
Results: 1 - 24 next
open access

Interactions of Ionic Liquids with Uranium and its Bioreduction

Description: We investigated the influence of ionic liquids (ILs) 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM]{sup +}[PF{sub 6}]{sup -}, N-ethylpyridinium trifluoroacetate [EtPy]{sup +}[CF{sub 3}COO]{sup -} and N-ethylpyridinium tetrafluoroborate [Et-Py]{sup +}[BF{sub 4}]{sup -} on uranium reduction by Clostridium sp. under anaerobic conditions. Potentiometric titration, UV-vis spectrophotometry, LC-MS and EXAFS analyses showed monodentate complexation between uranyl and BF{sub 4}{sup -} PF{sub 6}… more
Date: September 18, 2012
Creator: Zhang, C. & Francis, A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Subcellular localization of proteins in the anaerobic sulfate reducer Desulfovibrio vulgaris via SNAP-tag labeling and photoconversion

Description: Systems Biology studies the temporal and spatial 3D distribution of macromolecular complexes with the aim that such knowledge will allow more accurate modeling of biological function and will allow mathematical prediction of cellular behavior. However, in order to accomplish accurate modeling precise knowledge of spatial 3D organization and distribution inside cells is necessary. And while a number of macromolecular complexes may be identified by its 3D structure and molecular characteristics a… more
Date: June 1, 2010
Creator: Gorur, A.; Leung, C. M.; Jorgens, D.; Tauscher, A.; Remis, J. P.; Ball, D. A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Anaerobic Biotransformation and Mobility of Pu and of Pu-EDTA

Description: The enhanced mobility of radionuclides by co-disposed chelating agent, ethylenediaminetetraacetate (EDTA), is likely to occur only under anaerobic conditions. Our extensive effort to enrich and isolate anaerobic EDTA-degrading bacteria has failed. Others has tried and also failed. To explain the lack of anaerobic biodegradation of EDTA, we proposed that EDTA has to be transported into the cells for metabolism. A failure of uptake may contribute to the lack of EDTA degradation under anaerobic co… more
Date: November 20, 2009
Creator: Xun, Luying
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Arsenic chemistry in soils and sediments

Description: Arsenic is a naturally occurring trace element that poses a threat to human and ecosystem health, particularly when incorporated into food or water supplies. The greatest risk imposed by arsenic to human health results from contamination of drinking water, for which the World Health Organization recommends a maximum limit of 10 {micro}g L{sup -1}. Continued ingestion of drinking water having hazardous levels of arsenic can lead to arsenicosis and cancers of the bladder, skin, lungs and kidneys.… more
Date: October 15, 2009
Creator: Fendorf, S.; Nico, P.; Kocar, B.D.; Masue, Y. & Tufano, K.J.
Item Type: Refine your search to only Book
Partner: UNT Libraries Government Documents Department
open access

Stability of uranium incorporated into Fe(hydr)oxides under fluctuating redox conditions

Description: Reaction pathways resulting in uranium bearing solids that are stable (i.e., having limited solubility) under both aerobic and anaerobic conditions will limit dissolved concentrations and migration of this toxin. Here we examine the sorption mechanism and propensity for release of uranium reacted with Fe (hydr)oxides under cyclic oxidizing and reducing conditions. Upon reaction of ferrihydrite with Fe(II) under conditions where aqueous Ca-UO{sub 2}-CO{sub 3} species predominate (3 mM Ca and 3.8… more
Date: April 1, 2009
Creator: Stewart, B.D.; Nico, P.S. & Fendorf, S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Analysis of Metabolic Pathways and Fluxes in a Newly Discovered Thermophilic and Ethanol-Tolerant Geobacillus Strain

Description: A recently discovered thermophilic bacterium, Geobacillus thermoglucosidasius M10EXG, ferments a range of C5 (e.g., xylose) and C6 sugars (e.g., glucose) and istolerant to high ethanol concentrations (10percent, v/v). We have investigated the central metabolism of this bacterium using both in vitro enzyme assays and 13C-based flux analysis to provide insights into the physiological properties of this extremophile and explore its metabolism for bio-ethanol or other bioprocess applications. Our f… more
Date: January 20, 2009
Creator: Tang, Yinjie J.; Sapra, Rajat; Joyner, Dominique; Hazen, Terry C.; Myers, Samuel; Reichmuth, David et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Microbial Transformations of Actinides and Other Radionuclides

Description: Microorganisms can affect the stability and mobility of the actinides and other radionuclides released from nuclear fuel cycle and from nuclear fuel reprocessing plants. Under appropriate conditions, microorganisms can alter the chemical speciation, solubility and sorption properties and thus could increase or decrease the concentrations of radionuclides in solution in the environment and the bioavailability. Dissolution or immobilization of radionuclides is brought about by direct enzymatic ac… more
Date: January 7, 2009
Creator: Francis, A. J. & Dodge, C. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Corrosion-induced gas generation in a nuclear waste repository: Reactive geochemistry and multiphase flow effect

Description: Corrosion of steel canisters, stored in a repository for spent fuel and high-level nuclear wastes, leads to the generation and accumulation of hydrogen gas in the backfilled emplacement tunnels, which may significantly affect long-term repository safety. Previous studies used H{sub 2} generation rates based on the volume of the waste or canister material and the stoichiometry of the corrosion reaction. However, iron corrosion and H{sub 2} generation rates vary with time, depending on factors su… more
Date: October 15, 2008
Creator: Xu, T.; Senger, R. & Finsterle, S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

ELECTROCHEMICAL CORROSION REPORT FOR TANKS 241-AW-103 & 241-AZ-102 & 241-AN-106 & 241-AN-107 & 241-AY-101 & 241-AY-102

Description: Corrosion rates using supernatant samples retrieved from near the top of the liquid layer were determined for the tanks. Corrosion rates using settled solids (saltcake) were determined. The supernatant samples were tested as received without argon sparging. The settled solid sample segments were extruded under anaerobic condition and kept under a sweep of humidified argon gas during 'the electrochemical corrosion testing. The class of steel used to construct the tank in question was used, and t… more
Date: August 22, 2007
Creator: JB, DUNCAN
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Microbial Transformations of Radionuclides Released From Nuclear Fuel Reprocessing Plants.

Description: Microorganisms can affect the stability and mobility of the actinides U, Pu, Cm, Am, Np, and the fission products Tc, I, Cs, Sr, released from nuclear fuel reprocessing plants. Under appropriate conditions, microorganisms can alter the chemical speciation, solubility and sorption properties and thus could increase or decrease the concentrations of radionuclides in solution and the bioavailability. Dissolution or immobilization of radionuclides is brought about by direct enzymatic action or indi… more
Date: October 18, 2006
Creator: Francis, A. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

EVALUATING AN INNOVATIVE OXYGEN SENSOR FOR REMOTE SUBSURFACE OXYGEN MEASUREMENTS

Description: Oxygen is a primary indicator of whether anaerobic reductive dechlorination and similar redox based processes contribute to natural attenuation remedies at chlorinated solvent contaminated sites. Thus, oxygen is a viable indicator parameter for documenting that a system is being sustained in an anaerobic condition. A team of researchers investigated the adaptation of an optical sensor that was developed for oceanographic applications. The optical sensor, because of its design and operating prin… more
Date: October 12, 2006
Creator: Millings, Margaret R.; Riha, Brian D.; Hyde, W. Keith; Vangelas, Karen & Looney, Brian B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Biotransformation of PuEDTA: Implications to Pu Immobilization

Description: This project integrates three distinct goals to develop a fundamental understanding of the potential fate and disposition of plutonium in sediments that are co-contaminated with EDTA. The three objectives are: (1) Develop thermodynamic data for Pu-EDTA species and determine the dominant mobile form of Pu under anaerobic conditions. (2) Elucidate the mechanism and rates of Pu(IV) and Pu(IV)-EDTA reduction by metal-reducing bacteria and determine where the Pu is located (in solution, biosorbed, b… more
Date: June 1, 2006
Creator: Bolton, Harvey, Jr.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Evaluation of the effects of various culture condition on Cr (VI) reduction by Shewanella oneidensis MR-1 in a novel high-throughputmini-bioreactor

Description: The growth and Cr(VI) reduction by Shewanella oneidensisMR-1 was examined using a mini-bioreactor system that independentlymonitors and controls pH, dissolved oxygen, and temperature for each ofits 24, 10-mL reactors. Independent monitoring and control of eachreactor in the cassette allows the exploration of a matrix ofenvironmental conditions known to influence S. oneidensis chromiumreduction. S. oneidensis MR-1 grew in minimal medium without amino acidor vitamin supplementation under aerobic … more
Date: March 16, 2006
Creator: Tang, Yinjie J.; Laidlaw, David; Gani, Kishen & Keasling, Jay D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Coupling of Realistic Rate Estimates with Genomics for Assessing Contaminant Attenuation and Long-Term Plume Containment - Task 4: Modeling - Final Report

Description: Trichloroethene (TCE), a common groundwater contaminant, can be degraded under certain conditions by microorganisms that occur naturally in the subsurface. TCE can be degraded under anaerobic conditions to less chlorinated compounds and ultimately into the non-chlorinated, non-hazardous end product, ethene, via anaerobic reductive dechlorination (ARD). ARD is widely recognized as a TCE degradation mechanism, and occurs in active groundwater remediation and can occur during monitored natural att… more
Date: October 31, 2005
Creator: Starr, Robert C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

FINAL REPORT - Biogeochemistry of Uranium Under Reducing and Re-oxidizing Conditions:An Integrated Laboratory and Field Study and Acceptable Endpoints for Metals and Radionuclides: Quantifying the Stability of Uranium and Lead Immobilized Under Sulfate Reducing Conditions

Description: Our understanding of subsurface microbiology is hindered by the inaccessibility of this environment, particularly when the hydrogeologic medium is contaminated with toxic substances. Research in our labs indicated that the composition of the growth medium (e.g., bicarbonate complexation of U(VI)) and the underlying mineral phase (e.g., hematite) significantly affects the rate and extent of U(VI) reduction and immobilization through a variety of effects. Our research was aimed at elucidating tho… more
Date: October 7, 2005
Creator: Peyton, Brent; Amonette, James; Beyenal, Haluk; Geesey, Gill; Lewandowski, Zbigniew & Sani, Rajesh
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Enhancement of Bacterial Transport in Aerobic and Anaerobic Environments: Assessing the Effect of Metal Oxide Chemical Heterogeneities

Description: The goal of our research was to understand the fundamental processes that control microbial transport in physically and chemically heterogeneous aquifers and from this enhanced understanding determine the requirements for successful, field-scale delivery of microorganisms to metal contaminated subsurface sites. Our specific research goals were to determine; (1) the circumstances under which the preferential adsorption of bacteria to Fe, Mn, and Al oxyhydroxides influences field-scale bacterial … more
Date: September 30, 2005
Creator: Onstott, T. C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Biotransformation involved in sustained reductive removal of uranium in contaminant aquifers

Description: This report summarizes progress made from August 2004 to July 2005. During this period research focused primarily on obtaining a better understanding of the factors controlling the reduction of U(VI) during in situ uranium bioremediation as well as investigating the potential for using electrodes as an alternative electron donor to promote in situ uranium reduction. Analysis of the 2003 experiment at the field study site in Rifle, CO was completed. The results demonstrated the substantial heter… more
Date: June 1, 2005
Creator: Lovley, Derek R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Novel Imaging Techniques, Integrated with Mineralogical, Geochemical and Microbiological Characterization to Determine the Biogeochemical Controls....

Description: Tc(VII) will be reduced and precipitated in FRC sediments under anaerobic conditions in batch experiments (progressive microcosms). The complementary microcosm experiments using low pH/nigh nitrate sediments from 3 (near FW 009) are imminent, with the sediment cores already shipped to Manchester. HYPOTHESIS 2. Tc(VII) reduction and precipitation can be visualized in discrete biogeochemical zones in sediment columns using 99mTc and a gamma-camera. Preliminary experiments testing the use of 99mTc… more
Date: June 1, 2005
Creator: Lloyd, Jonathan R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Anaerobic, Nitrate-Dependent Oxidation of U(IV) Oxide Minerals by the Chemolithoautotrophic Bacterium Thiobacillus denitrificans

Description: Under anaerobic conditions and at circumneutral pH, cells of the widely-distributed, obligate chemolithoautotrophic bacterium Thiobacillus denitrificans oxidatively dissolved synthetic and biogenic U(IV) oxides (uraninite) in nitrate-dependent fashion: U(IV) oxidation required the presence of nitrate and was strongly correlated to nitrate consumption. This is the first report of anaerobic U(IV) oxidation by an autotrophic bacterium.
Date: June 25, 2004
Creator: Beller, H R
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Induced polarization response of microbial induced sulfideprecipitation

Description: A laboratory scale experiment was conducted to examine the use of induced polarization and electrical conductivity to monitor microbial induced sulfide precipitation under anaerobic conditions in sand filled columns. Three columns were fabricated; one for electrical measurements, one for geochemical sampling and a third non-inoculated column was used as a control. A continual upward flow of nutrients and metals in solution was established in each column. Desulfovibrio vulgaris microbes were inj… more
Date: June 4, 2004
Creator: Ntarlagiannis, Dimitrios; Williams, Kenneth Hurst; Slater, Lee & Hubbard, Susan
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Novel Imaging Techniques, Integrated with Mineralogical, Geochemical and Microbiological Characterization to Determine the Biogeochemical Controls....

Description: Aims and objectives Technetium-99 is a priority pollutant at numerous DOE sites, due to a combination of its long half life (2.1 x 105 years), high mobility as Tc(VII) (TcO4-; pertechnetate anion) in oxic waters, and bioavailability as a sulfate analog. Under anaerobic conditions, however, the radionuclide is far less mobile, forming insoluble Tc(IV) precipitates. As anaerobic microorganisms can reduce soluble Tc(VII) to insoluble Tc(IV), microbial metabolism may have the potential to treat sed… more
Date: June 1, 2004
Creator: Lloyd, Jonathan R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

DEVELOPMENT OF IMPROVED ANAEROBIC GROWTH OF BACILLUS MOJAVENSIS STRAIN JF-2 FOR THE PURPOSE OF IMPROVED ANAEROBIC BIOSURFACTANT PRODUCTION FOR ENHANCED OIL RECOVERY

Description: Our work focuses on the use of microorganisms to recover petroleum hydrocarbons that remain entrapped after current recovery technologies reach their economic limit. Capillary forces between the hydrocarbon and aqueous phases are largely responsible for trapping the hydrocarbons in the pores of the rock and large reductions in the interfacial tension between the hydrocarbon and aqueous phases are needed for hydrocarbon mobilization (1-3, 10, 11). Microorganisms produce a variety of biosurfactan… more
Date: May 31, 2004
Creator: McInerney, M.J.; Folmsbee, M. & Nagle, D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Biological Water-Gas Shift Conversion of Carbon Monoxide to Hydrogen: Milestone Completion Report

Description: This report summarizes the results of research and economic analysis on a biological water-gas shift process for the production of hydrogen. The organism Rubrivivax gelatinosus CBS is a photosynthetic bacteria which can perform the water-gas shift reaction under anaerobic conditions. The report describes some of the technical issues regarding the process, addresses some claimed benefits of the process and presents some results from economic studies of different process configurations.
Date: January 1, 2004
Creator: Amos, W. A.
Item Type: Refine your search to only Text
Partner: UNT Libraries Government Documents Department
Back to Top of Screen