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Metabolic Flux Analysis of Shewanella spp. Reveals Evolutionary Robustness in Central Carbon Metabolism

Description: Shewanella spp. are a group of facultative anaerobic bacteria widely distributed in marine and fresh-water environments. In this study, we profiled the central metabolic fluxes of eight recently sequenced Shewanella species grown under the same condition in minimal med-ium with [3-13C] lactate. Although the tested Shewanella species had slightly different growth rates (0.23-0.29 h31) and produced different amounts of acetate and pyruvate during early exponential growth (pseudo-steady state), the relative intracellular metabolic flux distributions were remarkably similar. This result indicates that Shewanella species share similar regulation in regard to central carbon metabolic fluxes under steady growth conditions: the maintenance of metabolic robustness is not only evident in a single species under genetic perturbations (Fischer and Sauer, 2005; Nat Genet 37(6):636-640), but also observed through evolutionary related microbial species. This remarkable conservation of relative flux profiles through phylogenetic differences prompts us to introduce the concept of metabotype as an alternative scheme to classify microbial fluxomics. On the other hand, Shewanella spp. display flexibility in the relative flux profiles when switching their metabolism from consuming lactate to consuming pyruvate and acetate.
Date: August 19, 2009
Creator: Tang, Yinjie J.; Martin, Hector Garcia; Dehal, Paramvir S.; Deutschbauer, Adam; Llora, Xavier; Meadows, Adam et al.
Partner: UNT Libraries Government Documents Department

Influences of Organic Carbon Supply Rate on Uranium Bioreduction in Initially Oxidizing, Contaminated Sediment

Description: Remediation of uranium (U) contaminated sediments through in-situ stimulation of bioreduction to insoluble UO{sub 2} is a potential treatment strategy under active investigation. Previously, we found that newly reduced U(IV) can be reoxidized under reducing conditions sustained by a continuous supply of organic carbon (OC) because of residual reactive Fe(III) and enhanced U(VI) solubility through complexation with carbonate generated through OC oxidation. That finding motivated this investigation directed at identifying a range of OC supply rates that is optimal for establishing U bioreduction and immobilization in initially oxidizing sediments. The effects of OC supply rate, from 0 to 580 mmol OC (kg sediment){sup -1} year{sup -1}, and OC form (lactate and acetate) on U bioreduction were tested in flow-through columns containing U-contaminated sediments. An intermediate supply rate on the order of 150 mmol OC (kg sediment){sup -1} year{sup -1} was determined to be most effective at immobilizing U. At lower OC supply rates, U bioreduction was not achieved, and U(VI) solubility was enhanced by complexation with carbonate (from OC oxidation). At the highest OC supply rate, resulting highly carbonate-enriched solutions also supported elevated levels of U(VI), even though strongly reducing conditions were established. Lactate and acetate were found to have very similar geochemical impacts on effluent U concentrations (and other measured chemical species), when compared at equivalent OC supply rates. While the catalysts of U(VI) reduction to U(IV) are presumably bacteria, the composition of the bacterial community, the Fe reducing community, and the sulfate reducing community had no direct relationship with effluent U concentrations. The OC supply rate has competing effects of driving reduction of U(VI) to low solubility U(IV) solids, as well as causing formation of highly soluble U(VI)-carbonato complexes. These offsetting influences will require careful control of OC supply rates in order to optimize bioreduction-based U stabilization.
Date: June 10, 2008
Creator: Tokunaga, Tetsu K.; Wan, Jiamin; Kim, Yongman; Daly, Rebecca A.; Brodie, Eoin L.; Hazen, Terry C. et al.
Partner: UNT Libraries Government Documents Department

Effect of Temperature on the Protonation of the TALSPEAK Ligands: Lactic and Diethylenetrinitropentaacetic Acids

Description: The protonation reactions of two ligands that play important roles in the TALSPEAK process for the separation of trivalent actinides from lanthanides, lactic acid and diethylenetrinitropentaacetic acid (DTPA), have been studied at variable temperatures. The protonation constants at 10-70 C were determined by titration potentiometry and the protonation enthalpies were determined at 25 C by titration microcalorimetry. The protonation constants remain essentially unchanged (25-70 C) within the experimental uncertainties, indicating that the effect of temperature on the protonation of lactate is insignificant. In contrast, the protonation constants of DTPA (log {beta}H's) generally decrease as the temperature is increased. Results from this study indicate that the effect of temperature on the protonation of DTPA could alter the speciation of metal ions (actinides and lanthanides) in the TALSPEAK system, since lower values of log{beta}H at higher temperatures suggest that the hydrogen ions would compete less strongly with the metal ions for the complexation of DTPA at higher temperatures.
Date: October 20, 2009
Creator: Tian, Guoxin & Rao, Linfeng
Partner: UNT Libraries Government Documents Department

Complexation of Lactate with Nd(III) and Eu(III) at Variable Temperatures: Studies by Potentiometry, Microcalorimetry, Optical Absorption and Luminescence Spectroscopy

Description: Complexation of neodymium(III) and europium(III) with lactate was studied at variable temperatures by potentiometry, absorption spectrophotometry, luminescence spectroscopy and microcalorimetry. Stability constants of three successive lactate complexes (ML{sup 2+}, ML{sup 2+} and ML{sub 3}(aq), where M stands for Nd and Eu, and L stands for lactate) at 10, 25, 40, 55 and 70 C were determined. The enthalpies of complexation at 25 C were determined by microcalorimetry. Thermodynamic data show that the complexation of trivalent lanthanides (Nd{sup 3+} and Eu{sup 3+}) with lactate is exothermic, and the complexation becomes weaker at higher temperatures. Results from optical absorption and luminescence spectroscopy suggest that the complexes are inner-sphere chelate complexes in which the protonated {alpha}-hydroxyl group of lactate participates in the complexation.
Date: October 1, 2010
Creator: Tian, Guoxin; Martin, Leigh R. & Rao, Linfeng
Partner: UNT Libraries Government Documents Department

Degradation of Isotopic Lactate and Acetate

Description: A scheme of glucose degradation has been validated by the use of intermediates of known isotopic composition. In this scheme: glucose {yields} lactic acid {yields} CO{sub 2} (C-3,4) + acetic acid {yields} CO{sub 2} (C-2,5) + acetone {yields} iodoform (C-1,6) + acetate (C-1,6; 2,5), it was found that (a) in the oxidation of lactic acid, approximately 4.7% of the acetic acid was oxidized to CO{sub 2}; and (b) under the conditions prescribed, BaCO{sub 3} from the degradation of Ba acetate contained approximately 1.5% of the activity of the methyl group.
Date: February 24, 1948
Creator: Aronoff, S.; Haas, V.A. & Fries, B.A.
Partner: UNT Libraries Government Documents Department

Advanced electrodialysis and pervaporation for fermentation-derived organic acids production.

Description: Lactate esters produced from carbohydrate have potential markets as nontoxic replacements for halogenated and toxic solvents and as feedstocks for large-volume chemicals and polymers. Argonne National Laboratory has developed a novel process for the production of high-purity lactate esters from carbohydrate. The process uses advanced electrodialysis and pervaporation technologies to overcome major technical barriers in product separation; more specifically, the process involves cation elimination without the generation of salt waste and efficient esterification for final purification. This patented process requires little energy input, is highly efficient and selective, eliminates the large volumes of salt waste produced by conventional processes, and significantly reduces manufacturing costs. The enabling membrane separation technologies make it technically and commercially feasible for lactate esters to penetrate the potential markets.
Date: November 18, 1998
Creator: Tsai, S. P.
Partner: UNT Libraries Government Documents Department

Advanced membrane separation technology for biosolvents. Final CRADA report.

Description: Argonne and Vertec Biosolvents investigated the stability and perfonnance for a number of membrane systems to drive the 'direct process' for pervaporation-assisted esterification to produce lactate esters. As outlined in Figure 1, the target is to produce ammonium lactate by fennentation. After purification and concentration, ammonium lactate is reacted with ethanol to produce the ester. Esterification is a reversible reaction so to drive the reaction forward, the produced ammonia and water must be rapidly separated from the product. The project focused on selecting pervaporation membranes with (1) acid functionality to facilitate ammonia separation and (2) temperature stability to be able to perform that reaction at as high a temperature as possible (Figure 2). Several classes of commercial membrane materials and functionalized membrane materials were surveyed. The most promising materials were evaluated for scale-up to a pre-commercial application. Over 4 million metric tons per year of solvents are consumed in the U.S. for a wide variety of applications. Worldwide the usage exceeds 10 million metric tons per year. Many of these, such as the chlorinated solvents, are environmentally unfriendly; others, such as the ethylene glycol ethers and N Methyl Pyrrolidone (NMP), are toxic or teratogenic, and many other petroleum-derived solvents are coming under increasing regulatory restrictions. High performance, environmentally friendly solvents derived from renewable biological resources have the potential to replace many of the chlorinated and petrochemical derived solvents. Some of these solvents, such as ethyl lactate; d-limonene, soy methyl esters, and blends ofthese, can give excellent price/perfonnance in addition to the environmental and regulatory compliance benefits. Advancement of membrane technologies, particularly those based on pervaporation and electrodialysis, will lead to very efficient, non-waste producing, and economical manufacturing technologies for production of ethyl lactate and other esters.
Date: February 8, 2010
Creator: Snyder, S. W.
Partner: UNT Libraries Government Documents Department

Design and Evaluation of Ionic Liquids as Novel CO2 Absorbents

Description: Progress from the third quarter 2006 activity on the project ''Design and Evaluation of Ionic Liquids as Novel CO{sub 2} Absorbents'' is provided. Major activities in two areas are reported: property measurement and molecular modeling. We have measured CO{sub 2} solubility in an ammonium lactate ionic liquid. Previous work has shown that the lactate anion enables chemical complexation to occur. We hypothesized that the lactate anion would not be as effective in complexing when paired with an ammonium cation as compared to when it is paired with an imidazolium cation. The results confirm this. We also measured CO{sub 2} solubility in a functionalized ionic liquid containing an amine group. These so-called task specific ionic liquids (TSILs) are expected to have dramatically higher CO{sub 2} solubility than physical absorbents. We report isotherms as well as entropies and enthalpies of absorption for CO{sub 2} in one TSIL. CO{sub 2} solubilities are higher in this compound than in any previous IL we have observed. Finally, we also developed a new simulation method that will enable us to compute full isotherms of gases in ionic liquids. So far, we have tested the method against model systems and found it to be highly effective.
Date: September 30, 2006
Creator: Maginn, Edward J.
Partner: UNT Libraries Government Documents Department

Field Deployment for In-situ Metal and Radionuclide Stabilization by Microbial Metabolites

Description: A novel biotechnology is reported here that was demonstrated at SRS that facilitates metal and actinide immobilization by incorporating the physiology and ecology of indigenous bacteria. This technology is based on our previous work with pyomelanin-producing bacteria isolated from SRS soils. Through tyrosine supplementation, overproduction of pyomelanin was achieved, which lead ultimately to metal and actinide immobilization, both in-vitro and in-situ. Pyomelanin is a recalcitrant microbial pigment and a humic type compound in the class of melanin pigments. Pyomelanin has electron shuttling and metal chelation capabilities and thus accelerates the bacterial reduction and/or immobilization of metals. Pyomelanin is produced outside the cell and either diffuses away or attaches to the cell surface. In either case, the reduced pyomelanin is capable of transferring electrons to metals as well as chelating metals. Because of its recalcitrance and redox cycling properties, pyomelanin molecules can be used over and over again for metal transformation. When produced in excess, pyomelanin produced by one bacterial species can be used by other species for metal reduction, thereby extending the utility of pyomelanin and further accelerating metal immobilization rates. Soils contaminated with Ni and U were the focus of this study in order to develop in-situ, metal bioimmobilization technologies. We have demonstrated pyomelanin production in soil from the Tims Branch area of SRS as a result of tyrosine amendments. These results were documented in laboratory soil column studies and field deployment studies. The amended soils demonstrated increased redox behavior and sequestration capacity of U and transition metals following pyomelanin production. Treatments incorporating tyrosine and lactate demonstrated the highest levels of pyomelanin production. In order to determine the potential use of this technology at other areas of SRS, pyomelanin producing bacteria were also quantified from metal contaminated soils at TNX and D areas of SRS. A bacterial culture collection ...
Date: September 26, 2005
Creator: Turick, C. E.; Knox, A. S.; Dixon, K. L.; Roseberry, R. J. & Kritzas, Y. G
Partner: UNT Libraries Government Documents Department

Identification of Molecular and Cellular Responses of Desulfovibrio vulgaris Biofilms under Culture Conditions Relevant to Field Conditions for Bioreduction

Description: Desulfovibrio vulgaris ATCC29579 is a sulfate- reducing bacterium (SRB) that is commonly used as a model for direct and indirect heavy metal reduction, and can also be a causitative agent of metal corrosion. During growth with lactate and sulfate, internal carbohydrate levels increased throughout exponential-phase, and peaked as the cells transitioned to stationary-phase. The carbohydrate to protein ratio (C:P) peaked at 0.05 ug/ug as the cells transitioned to stationary-phase, and then declined to 0.02 ug/ug during extended stationary-phase. In contrast, a strain of D. vulgaris that does not contain the megaplasmid, maintained higher internal carbohydrate levels and the C:P ratio peaked at 0.1 ug/ug (2-fold increase compared to wild-type). Under the tested growth conditions, we observed biofilm formation in wild-type cells, but the plasmid-less strain formed less biofilm (2-fold decrease). We hypothesized that carbohydrate was re-allocated to the external cell proper for biofilm formation. However, biofilm contained relatively little carbohydrate (0.6 to 1.0 ug/ml) and had a similar C:P ratio compared to wild-type early stationary-phase cells. Staining with calcafluor white also indicated the presence of little external carbohydrate in D. vulgaris biofilms. Less biofilm was formed in the presence of protinease K, trypsin, and chymotrypsin, however, the growth of planktonic cells was not affected. In addition, when D. vulgaris biofilm was treated with a protease, less biofilm was observed. Electron micrographs suggested the presence of filaments between the biofilm cells, and filaments appeared to be susceptible to protease treatment. Biofilm filtrates contained soluble protein, and SDS-PAGE analysis suggested different polypeptide profiles between a filtrate, a planktonic, and a biofilm sample.
Date: June 1, 2006
Creator: Fields, Matthew W.
Partner: UNT Libraries Government Documents Department


Description: In the mammary gland of nonruminant animals, glucose is utilized in a characteristic and unique way during lactation. We have measured the incorporation of glucose carbon from [U-{sup 14}C] glucose into intermediary metabolites and metabolic products in mammary epithelial cells from virgin, pregnant, and lactating mice and demonstrate that glucose metabolite patterns can be used to recognize stages of differentiated function. For these cells, the rates of synthesis of glycogen and lactose, the ratio of lactate to alanine, and the ratio of citrate to malate were important parameters in identifying the degree of expression of differentiation. We further show that these patterns can be used as markers to determine the differentiated state of cultured mammary epithelial cells. Cells maintained on plastic substrates lose their distinctive glucose metabolite patterns while those on floating collagen gels do not. Cells from pregnant mice have a pattern similar to freshly isolated cells from pregnant mice. The pattern of cells from lactating mice is different from that of the cells of origin, and resembles that of the cells from pregnant mice. Our findings suggest that the floating collagen gels under the culture conditions used in these experiments provide an environment for the functional expression of the pregnant state, while additional factors are needed for the expression of the lactating state.
Date: June 1, 1980
Creator: Emerman, J.T.; Bartley, J.C. & Bissell, M.J.
Partner: UNT Libraries Government Documents Department

D-Area Sulfate Reduction DIW-1 Organic Application Field Study

Description: An acidic/metals/sulfate, groundwater contaminant plume emanates from the diarrhea Coal Pile Runoff Basin (DCPRB) at the Savannah River Site (SRS), due to the contaminated runoff the basin receives from the D-Area coal pile. From a previous feasibility evaluation and laboratory testing, it was concluded that the plume could be remediated with sulfate reduction remediation combined with monitored natural attenuation (MNA). Additionally these previous studies recommended that soybean oil and sodium lactate be utilized as organic substrates for sulfate reducing bacteria (SRB) during a subsequent sulfate reduction, pilot scale, field demonstration. The soybean oil was to be tested as a long-term, slow release, organic substrate, and the sodium lactate was to be tested as a short-term, immediately available, organic substrate. The subsequent sulfate reduction, pilot scale, field demonstration consisted of the following: (1) Approximately 825 gallons of soybean oil was injected into both the south and north wings of the existing D-Area interceptor well. (2) Approximately 227.5 gallons of sodium lactate and 1169 gallons of groundwater from a background well were injected into the south wing only. The groundwater was used to reduce the viscosity of the sodium lactate for injection, to flush the sodium lactate out of the injection point screen zones, and to provide bioaugmentation (i.e. the addition of SRB). Both pre-injection and post-injection monitoring and sampling and analysis were conducted in order to evaluate the impact of organic substrate injection on soluble organic, sulfate, nutrient, microbe, hydrogen sulfide, pH, Eh, and metal concentrations (i.e. the ability to promote sulfate reduction remediation of the plume). Overall it is clear from this field demonstration that both soybean oil and sodium lactate provided a suitable organic substrate to promote SRB growth. The SRB growth promoted by both soybean oil and sodium lactate resulted in sulfate reduction remediation as evidenced by the ...
Date: January 12, 2003
Creator: Phifer, M.A.
Partner: UNT Libraries Government Documents Department

Pacific Lamprey Research and Restoration Project : Annual Report 1999.

Description: This report summarizes results of research activities conducted from 1996 through 1999. The findings in these chapters represent the efforts of the Confederated Tribes of the Umatilla Indian Reservation (CTUIR) and collaborative efforts among other researchers working on Pacific lampreys (Lampetra tridentata) under this project. The findings in these chapters will help management and recovery of Pacific lampreys in the Columbia River Basin. Traditional Ecological Knowledge (TEK) of Pacific lampreys from tribal members within the Confederated Tribes of the Umatilla Indian Reservation was useful in gaining baseline life history information. Tribal members described harvesting two types of lampreys from spring through fall, the short brown type and the long dark type. Lamprey spawning distribution was from the mouth to the headwaters in the Umatilla River. Larval lampreys were observed in the mud and sand areas of the river. Tribal members observed major declines in lampreys within the Columbia River basin. Larval Pacific lampreys were distributed throughout the John Day River basin. Larval distribution in the other subbasins was patchy and limited to the lower reaches of the streams. Larval densities were highly variable in the Middle Fork John Day and North Fork John Day rivers, as opposed to the Main stem John Day River. Larval lengths varied little in the Middle Fork John Day and North Fork John Day rivers, but were highly variable in the Main stem John Day River. Larval abundance decreased as we moved upstream in the Columbia and Snake rivers. In addition, we found strong evidence for lack of larval recruitment as distance increased from the mouth of the Columbia River. We identified clinical indicators of stress in adult Pacific lampreys. Plasma glucose became elevated soon after acute stress and remained elevated for one week. Plasma lactate also became elevated by 30 minutes; however, it decreased ...
Date: October 1, 2001
Creator: Close, David A.
Partner: UNT Libraries Government Documents Department

New electrolyte systems for capillary zone electrophoresis of metal cations and non-ionic organic compounds

Description: Excellent separations of metal ions can be obtained very quickly by capillary electrophoresis provided a weak complexing reagent is incorporated into the electrolyte to alter the effective mobilities of the sample ions. Indirect photometric detection is possible by also adding a UV-sensitive ion to the electrolyte. Separations are described using phthalate, tartrate, lactate or hydroxyisobutyrate as the complexing reagent. A separation of twenty-seven metal ions was achieved in only 6 min using a lactate system. A mechanism for the separation of lanthanides is proposed for the hydroxyisobutyrate system.
Date: June 19, 1995
Creator: Shi, Y.
Partner: UNT Libraries Government Documents Department

Sigma Team for Minor Actinide Separation: PNNL FY 2010 Status Report

Description: Work conducted at Pacific Northwest National Laboratory (PNNL) in FY 2010 addressed two lines of inquiry. The two hypotheses put forth were: 1. The extractants from the TRUEX( ) process (CMPO)( ) and from the TALSPEAK( ) process (HDEHP)( ) can be combined into a single process solvent to separate 1) the lanthanides and actinides from acidic high-level waste and 2) the actinides from the lanthanides in a single solvent extraction process. (Note: This combined process will hereafter be referred to as the TRUSPEAK process.) A series of empirical measurements performed (both at PNNL and Argonne National Laboratory) in FY 2009 supported this hypothesis, but also indicated some nuances to the chemistry. Lanthanide/americium separation factors of 12 and higher were obtained with a prototypic TRUSPEAK solvent when extracting the lanthanides from a citrate-buffered DTPA( ) solution. Although the observed separation factors are sufficiently high to design an actinide/lanthanide separation process, a better understanding of the chemistry is expected to lead to improved solvent formulations and improved process performance. Work in FY 2010 focused on understanding the synergistic extraction behavior observed for Nd(III) and Am(III) when extracted into mixtures of CMPO and HDEHP. The interaction between CMPO and HDEHP in dodecane was investigated by 31P NMR spectroscopy, and an adduct of the type CMPO•HDEHP was found to form. The formation of this adduct will reduce the effective extractant concentrations and must be taken into account when modeling metal ion extraction data in this system. Studies were also initiated to determine the Pitzer parameters for Nd(III) in lactate media. 2. Higher oxidation states (e.g., +5 and +6) of Am can be stabilized in solution by complexation with uranophilic ligands, and this chemistry can be exploited to separate Am from Cm. To test this hypothesis, the previously reported stereognostic uranophilic ligands NPB( ) ...
Date: August 24, 2010
Creator: Lumetta, Gregg J.; Sinkov, Sergey I.; Neiner, Doinita; Levitskaia, Tatiana G.; Braley, Jenifer C.; Carter, Jennifer C. et al.
Partner: UNT Libraries Government Documents Department

Novel Regenerated Solvent Extraction Processes for the Recovery of Carboxylic Acids or Ammonia from Aqueous Solutions Part I. Regeneration of Amine-Carboxylic Acid Extracts

Description: Two novel regenerated solvent extraction processes are examined. The first process has the potential to reduce the energy costs inherent in the recovery of low-volatility carboxylic acids from dilute aqueous solutions. The second process has the potential for reducing the energy costs required for separate recovery of ammonia and acid gases (e.g. CO{sub 2} and H{sub 2}S) from industrial sour waters. The recovery of carboxylic acids from dilute aqueous solution can be achieved by extraction with tertiary amines. An approach for regeneration and product recovery from such extracts is to back-extract the carboxylic acid with a water-soluble, volatile tertiary amine, such as trimethylamine. The resulting trimethylammonium carboxylate solution can be concentrated and thermally decomposed, yielding the product acid and the volatile amine for recycle. Experimental work was performed with lactic acid, succinic acid, and fumaric acid. Equilibrium data show near-stoichiometric recovery of the carboxylic acids from an organic solution of Alamine 336 into aqueous solutions of trimethylamine. For fumaric and succinic acids, partial evaporation of the aqueous back extract decomposes the carboxylate and yields the acid product in crystalline form. The decomposition of aqueous solutions of trimethylammonium lactates was not carried out to completion, due to the high water solubility of lactic acid and the tendency of the acid to self-associate. The separate recovery of ammonia and acid gases from sour waters can be achieved by combining steam-stripping of the acid gases with simultaneous removal of ammonia by extraction with a liquid cation exchanger. The use of di-2,4,4-trimethylpentyl phosphinic acid as the liquid cation exchanger is explored in this work. Batch extraction experiments were carried out to measure the equilibrium distribution ratio of ammonia between an aqueous buffer solution and an organic solution of the phosphinic acid (0.2N) in Norpar 12. The concentration-based distribution ratios increase from 0.11 to 0.46 ...
Date: March 1, 1990
Creator: Poole, L.J. & King, C.J.
Partner: UNT Libraries Government Documents Department

The electron transfer system of syntrophically grown Desulfovibrio vulgaris

Description: Interspecies hydrogen transfer between organisms producing and consuming hydrogen promotes the decomposition of organic matter in most anoxic environments. Although syntrophic couplings between hydrogen producers and consumers are a major feature of the carbon cycle, mechanisms for energy recovery at the extremely low free energies of reactions typical of these anaerobic communities have not been established. In this study, comparative transcriptional analysis of a model sulfate-reducing microbe, Desulfovibrio vulgaris Hildenborough, suggested the use of alternative electron transfer systems dependent upon growth modality. During syntrophic growth on lactate with a hydrogenotrophic methanogen, D. vulgaris up-regulated numerous genes involved in electron transfer and energy generation when compared with sulfate-limited monocultures. In particular, genes coding for the putative membrane-bound Coo hydrogenase, two periplasmic hydrogenases (Hyd and Hyn) and the well-characterized high-molecular weight cytochrome (Hmc) were among the most highly expressed and up-regulated. Additionally, a predicted operon coding for genes involved in lactate transport and oxidation exhibited up-regulation, further suggesting an alternative pathway for electrons derived from lactate oxidation during syntrophic growth. Mutations in a subset of genes coding for Coo, Hmc, Hyd and Hyn impaired or severely limited syntrophic growth but had little affect on growth via sulfate-respiration. These results demonstrate that syntrophic growth and sulfate-respiration use largely independent energy generation pathways and imply that understanding of microbial processes sustaining nutrient cycling must consider lifestyles not captured in pure culture.
Date: May 1, 2009
Creator: Walker, C. B.; He, Z.; Yang, Z.K.; Ringbauer, J. A., Jr.; He, Q.; Zhou, J. et al.
Partner: UNT Libraries Government Documents Department

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 injected into the middle of the geochemical and electrical columns. Iron and zinc sulfides precipitated along a microbial action front as a result of sulfate reduction due by Desulfovibrio vulgaris. The precipitation front initially developed near the microbial injection location, and subsequently migrated towards the nutrient inlet, as a result of chemotaxis by Desulfovibrio vulgaris. Sampling during and subsequent to the experiment revealed spatiotemporal changes in the biogeochemical measurements associated with microbial sulfate reduction. Conductivity measurements were insensitive to all biogeochemical changes occurred within the column. Changes in the IP response (of up to 14 mrad)were observed to coincide in place and in time with the active microbe respiration/sulfide precipitation front as determined from geochemical sampling. The IP response is correlated with the lactate concentration gradient, an indirect measurement of microbial metabolism, suggesting the potential of IP as a method for monitoring microbial respiration/activity. Post experimental destructive sample analysis and SEM imaging verified the geochemical results and supported our hypothesis that microbe induced sulfide precipitation is directly detectable using electrical methods. Although the processes not fully understood, the IP response appears to be sensitive to this anaerobic microbial precipitation, suggesting a possible novel application for the IP method.
Date: June 4, 2004
Creator: Ntarlagiannis, Dimitrios; Williams, Kenneth Hurst; Slater, Lee & Hubbard, Susan
Partner: UNT Libraries Government Documents Department

Thermodynamics and Kinetics of Advanced Separations Systems – FY 2010 Summary Report

Description: This report presents a summary of the work performed in the area of thermodynamics and kinetics of advanced separations systems under the Fuel Cycle Research and Development (FCR&D) program during FY 2010. Thermodynamic investigations into metal extraction dependencies on lactate and HDEHP have been performed. These metal distribution studies indicate a substantial deviation from the expected behavior at conditions that are typical of TALSPEAK process operational platform. These studies also identify that no thermodynamically stable mixed complexes exist in the aqueous solutions and increasing the complexity of the organic medium appears to influence the observed deviations. Following on from this, the first calorimetric measurement of the heat of extraction of americium across a liquid-liquid boundary was performed.
Date: September 1, 2010
Creator: Martin, Leigh R. & Zalupski, Peter R.
Partner: UNT Libraries Government Documents Department

Mesoscale Tank Experiments for Investigating Carbon Tetrachloride Biodegradation

Description: Mesoscale tank experiments were performed to simulate bioremediation of saturated zone carbon tetrachloride (CCl4) originating from a vadose zone carbon tetrachloride source. The mesoscale tank is 2-m wide by 2-m high by 3-m long and was constructed of stainless steel, yielding a total volume of 12 m3. Simulated geology within the tank consisted of two unconsolidated sand layers separated by a clay layer containing variable-sized stainless steel tubes that represented fractures within a consolidated porous medium. The thickness of the upper sand layer was approximately 55 cm, the thickness of the virtual fracture layer was 25 cm, and the thickness of the lower sand layer was approximately 98 cm. The water table was located at an elevation of approximately 54 cm from the bottom of the tank. CCl4 was added to the sealed tank by pouring 500 ml of neat CCl4 into a beaker buried approximately 10 cm below the upper sand surface through a stainless steel tube. The CCl4 was then allowed to partition through the reactor over time, eventually coming to equilibrium. Once CCl4 equilibrium had occurred in the saturated zone (~500 ppb); the reactor was bioaugmented with a CCl4 degrading culture enriched from the Subsurface Disposal Area at the INEEL. The culture was grown to a cell density of ~ 1.0 x 108 cells/ml and injected into the simulated aquifer through a center sampling port. Following injection of the culture, an initial aliquot of lactate (1,000 g/L), nitrogen, and phosphorus were added to the reactor. Lactate was injected every 3 – 5 days for one month. After 1 month of operation, a continuous supply of lactate (1,000 g/L) was pumped into the reactor at an average rate of 50 mL/min. CCl4 concentrations in the unsaturated zone were measured using hollow fiber membrane samplers, while liquid samples were ...
Date: June 1, 2005
Creator: Lee, Brady D. & Lenhard, Robert J.
Partner: UNT Libraries Government Documents Department

D-Area Sulfate Reduction Studty Comprehensive Final Report

Description: An acidic/metals/sulfate, groundwater contaminant plume emanates from the D-Area Coal Pile Runoff Basin (DCPRB) at the Savannah River Site (SRS), due to the contaminated runoff the basin receives from the D-Area coal pile. A Treatability Study Work Plan (TSWP) (WSRC 2001) was implemented to evaluate the potential for the sulfate reduction remediation of the DCPRB acidic/metals/sulfate, groundwater contaminant plume. The following studies, implemented as part of the TSWP, are documented herein: Bacteria Population and Organic Selection Laboratory Testing; DTT-1 Trench Evaluation; DIW-1 Organic Application Field Study-Part 1; and DIW-1 Organic Application Field Study-Part 2. Evaluation of sulfate reduction applicability actually began with a literature search and feasibility report in mid 2001, which fed into the TSWP. Physical completion of TSWP work occurred in late 2004 with the completion of the DIW-1 Organic Application Field Study-Part 2. The following are the primary conclusions drawn based upon this 3-year effort: (1) Pure soybean oil provides a long-term, indirect, SRB carbon source that floats on top of the water table (by indirect it means that the soybean oil must be degraded by other microbes prior to utilization by SRB) for the promotion of sulfate reduction remediation. Soybean oil produces no known SRB inhibitory response and therefore large quantities can be injected. (2) Sodium lactate provides a short-term, immediately available, direct, SRB carbon source that is miscible with the groundwater and therefore flows with the groundwater until it has been completely utilized for the promotion of sulfate reduction remediation. Lactate at elevated concentrations (greater than 6 g/L) does produce a SRB inhibitory response and therefore small quantities must be injected frequently. (3) The use of limestone to buffer the contaminated groundwater facilitates sulfate reduction remediation through the injection of organic substrate. Additionally conclusions and recommendations are made in Sections 8 and 9 regarding continuation ...
Date: February 11, 2005
Creator: Phifer, M
Partner: UNT Libraries Government Documents Department

Toward understanding the thermodynamics of TALSPEAK process. Medium effects on actinide complexation

Description: The ingenious combination of lactate and diethylenetriamine-N,N,N’,N”,N”-pentaacetic acid (DTPA) as an aqueous actinide-complexing medium forms the basis of the successful separation of americium and curium from lanthanides known as the TALSPEAK process. While numerous reports in the prior literature have focused on the optimization of this solvent extraction system, considerably less attention has been devoted to the understanding of the basic thermodynamic features of the complex fluids responsible for the separation. The available thermochemical information of both lactate and DTPA protonation and metal complexation reactions are representative of the behavior of these ions under idealized conditions. Our previous studies of medium effects on lactate protonation suggest that significant departures from the speciation predicted based on reported thermodynamic values should be expected in the TALSPEAK aqueous environment. Thermodynamic parameters describing the separation chemistry of this process thus require further examination at conditions significantly removed from conventional ideal systems commonly employed in fundamental solution chemistry. Such thermodynamic characterization is the key to predictive modelling of TALSPEAK. Improved understanding will, in principle, allow process technologists to more efficiently respond to off-normal conditions during large scale process operation. In this report, the results of calorimetric and potentiometric investigations of the effects of aqueous electrolytes on the thermodynamic parameters for lactate protonation and lactate complexation of americium and neodymium will be presented. Studies on the lactate protonation equilibrium will clearly illustrate distinct thermodynamic variations between strong electrolyte aqueous systems and buffered lactate environment.
Date: July 1, 2009
Creator: Zalupski, Peter R; Martin, Leigh R; Nash, Ken; Nakamura, Yoshinobu & Yamamoto, Masahiko
Partner: UNT Libraries Government Documents Department

Field Investigations of Lactate-Stimulated Bioreduction of Cr(VI) at Hanford 100H

Description: The overall objective of this paper is to carry out field investigations to assess the potential for immobilizing and detoxifying chromium-contaminated groundwater using lactate-stimulated bioreduction of Cr(VI) to Cr(III) at the Hanford 100H site.
Date: April 20, 2005
Creator: Hazen, T. C.; Faybishenko, B.; Joyner, D.; Borglin, S.; Brodie, E.; Hubbard, S. et al.
Partner: UNT Libraries Government Documents Department

A Thermodynamic Model for Acetate, Lactate, and Oxalate Complexation with Am(III), Th(IV), Np(V), and U(VI) Valid to High Ionic Strength

Description: The organic ligands acetate, lactate, oxalate and EDTA have been identified as components of wastes targeted for disposal in the Waste Isolation Pilot Plant (WIPP) located in Southeastern New Mexico. The presence of these ligands is of concern because complexation of the actinides with the ligands may increase dissolved actinide concentrations and impact chemical retardation during transport. The current work considers the complexation of Am(III), Th (IV), Np(V), and U(W) with two of the organic ligands, acetate and lactate, in NaCl media from dilute through high concentration. A thermodynamic model for actinide complexation with the organic ligands has been developed based on the Pitzer activity coefficient formalism and the Harvie-Moller-Weare, Felmy-Weare database for describing brine evaporite systems. The model was parameterized using first apparent stability constant data from the literature. Because of complexation of other metal ions (Fe, Mg, Ni, Pb, etc.) present in the WIPP disposal room with the organic ligands, preliminary results from model calculations indicate the organic ligands do not significantly increase dissolved actinide concentrations.
Date: January 15, 1999
Creator: Bynaum, R.V.; Free, S.J. & Moore, R.C.
Partner: UNT Libraries Government Documents Department