Research Interests: Chemistry, Electron Microscopy, Environmental Chemistry, Medicine, Multidisciplinary, and 15 moreCarbon Monoxide, Applied, Applied Environmental Microbiology, Ground Water, Drinking Water, Sterilization, Bioaugmentation, Carcinogens, AQUIFER, Electrophoresis, Ozone, Bacterial Adhesion, Betaproteobacteria, Electrophoretic Mobility, and Electrostatic interaction
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Research Interests: Chemistry, Kinetics, Bioremediation, Water Pollution, Medicine, and 14 moreMultidisciplinary, Transport, Dehalococcoides, Porous Media, Ground Water, Bioaugmentation, Aqueous Two Phase System, Reductive Dechlorination, Trichloroethylene, DCE, Vinyl Chloride Monomer, Decontamination, Aqueous Solution, and Kinetic model
Two differentially labeled bacterial strains were monitored in near-real time during two field-scale bacterial transport experiments in a shallow aquifer in July 2000 and July 2001. Comamonas sp. strain DA001 and Acidovorax sp. strain... more
Two differentially labeled bacterial strains were monitored in near-real time during two field-scale bacterial transport experiments in a shallow aquifer in July 2000 and July 2001. Comamonas sp. strain DA001 and Acidovorax sp. strain OY-107 were grown and labeled with the vital fluorescent stain TAMRA/SE (5 [and -6]-carboxytetramethylrhodamine, succinimidyl ester) or CFDA/SE (5 [and -6]-carboxyfluorescein diacetate, succinimidyl ester). Fluorescently labeled cells and a conservative bromide tracer were introduced into a suboxic superficial aquifer, followed by groundwater collection from down-gradient multilevel samplers. Cells were enumerated in the field by microplate spectrofluorometry, with confirmatory analyses for selected samples done in the laboratory by epifluorescence microscopy, flow cytometry, and ferrographic capture. There was general agreement in the results from all of the vital-stain-based enumeration methods, with differences ranging from <10% up to 40% for the...
Research Interests: Chemistry, Environmental Monitoring, Fluorescent Dyes and Reagents, Medicine, Enumeration, and 15 moreConcentration, Applied, Method, Applied Environmental Microbiology, Bacteria, Application, AQUIFER, Ecosystem, Coastal Zone, Coastal Plain, Environmental Pollutants, Geologic Sediments, Fluorescent Labelling, Ethidium bromide, and fluorescent dyes
The gasoline oxygenate methyl tert -butyl ether (MTBE) has become a widespread contaminant in groundwater throughout the United States. Bioaugmentation of aquifers with MTBE-degrading cultures may be necessary to enhance degradation of... more
The gasoline oxygenate methyl tert -butyl ether (MTBE) has become a widespread contaminant in groundwater throughout the United States. Bioaugmentation of aquifers with MTBE-degrading cultures may be necessary to enhance degradation of the oxygenate in some locations. However, poor cell transport has sometimes limited bioaugmentation efforts in the past. The objective of this study was to evaluate the transport characteristics of Hydrogenophaga flava ENV735, a pure culture capable of growth on MTBE, and to improve movement of the strain through aquifer solids. The wild-type culture moved only a few centimeters in columns of aquifer sediment. An adhesion-deficient variant ( H. flava ENV735:24) of the wild-type strain that moved more readily through sediments was obtained by sequential passage of cells through columns of sterile sediment. Hydrophobic and electrostatic interaction chromatography revealed that the wild-type strain is much more hydrophobic than the adhesion-deficient var...
Research Interests: Chemistry, Electron Microscopy, Environmental Chemistry, Medicine, Multidisciplinary, and 15 moreCarbon Monoxide, Applied, Applied Environmental Microbiology, Ground Water, Drinking Water, Sterilization, Bioaugmentation, Carcinogens, AQUIFER, Electrophoresis, Ozone, Bacterial Adhesion, Betaproteobacteria, Electrophoretic Mobility, and Electrostatic interaction
We isolated an MTBE-degrading bacterium, Hydrogenophaga flava ENV 735, that grows slowly on MTBE, but grows rapidly on MTBE or tertiary butyl alcohol(TBA) in the presence of a small amount of yeast extract(0. 01%). The strain mineralizes... more
We isolated an MTBE-degrading bacterium, Hydrogenophaga flava ENV 735, that grows slowly on MTBE, but grows rapidly on MTBE or tertiary butyl alcohol(TBA) in the presence of a small amount of yeast extract(0. 01%). The strain mineralizes uniformly labeled[14 C] MTBE to ...
Several propane-oxidizing bacteria were tested for their ability to degrade gasoline oxygenates, including methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME). Both a laboratory strain and... more
Several propane-oxidizing bacteria were tested for their ability to degrade gasoline oxygenates, including methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME). Both a laboratory strain and natural isolates were able to degrade each compound after growth on propane. When propane-grown strain ENV425 was incubated with 20 mg of uniformly labeled [14C]MTBE per liter, the strain converted > 60% of the added MTBE to 14CO2 in < 30 h. The initial oxidation of MTBE and ETBE resulted in the production of nearly stoichiometric amounts of tert-butyl alcohol (TBA), while the initial oxidation of TAME resulted in the production of tert-amyl alcohol. The methoxy methyl group of MTBE was oxidized to formaldehyde and ultimately to CO2. TBA was further oxidized to 2-methyl-2-hydroxy-1-propanol and then 2-hydroxy isobutyric acid; however, neither of these degradation products was an effective growth substrate for the propane oxidizers. Analysis of cel...
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1,2-Dibromethane (EDB) is a toxic fuel additive that likely occurs at many sites where leaded fuels have impacted groundwater. This study quantified carbon (C) isotope fractionation of EDB associated with anaerobic and aerobic... more
1,2-Dibromethane (EDB) is a toxic fuel additive that likely occurs at many sites where leaded fuels have impacted groundwater. This study quantified carbon (C) isotope fractionation of EDB associated with anaerobic and aerobic biodegradation, abiotic degradation by iron sulfides, and abiotic hydrolysis. These processes likely contribute to EDB degradation in source zones (biodegradation) and in more dilute plumes (hydrolysis). Mixed anaerobic cultures containing dehalogenating organisms (e.g., Dehaloccoides spp.) were examined, as were aerobic cultures that degrade EDB cometabolically. Bulk C isotope enrichment factors (ε) associated with biological degradation covered a large range, with mixed anaerobic cultures fractionating more (ε from -8 to -20‰) than aerobic cultures (ε from -3 to -6‰). ε magnitudes associated with the abiotic processes (dihaloelimination by FeS/FeS and hydrolysis) were large but fairly well constrained (ε from -19 to -29‰). As expected, oxidative mechanisms f...
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ABSTRACTKinetic isotopic fractionation of carbon and nitrogen during RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) biodegradation was investigated with pure bacterial cultures under aerobic and anaerobic conditions. Relatively large bulk... more
ABSTRACTKinetic isotopic fractionation of carbon and nitrogen during RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) biodegradation was investigated with pure bacterial cultures under aerobic and anaerobic conditions. Relatively large bulk enrichments in15N were observed during biodegradation of RDX via anaerobic ring cleavage (ε15N = −12.7‰ ± 0.8‰) and anaerobic nitro reduction (ε15N = −9.9‰ ± 0.7‰), in comparison to smaller effects during biodegradation via aerobic denitration (ε15N = −2.4‰ ± 0.2‰).13C enrichment was negligible during aerobic RDX biodegradation (ε13C = −0.8‰ ± 0.5‰) but larger during anaerobic degradation (ε13C = −4.0‰ ± 0.8‰), with modest variability among genera. Dual-isotope ε13C/ε15N analyses indicated that the three biodegradation pathways could be distinguished isotopically from each other and from abiotic degradation mechanisms. Compared to the initial RDX bulk δ15N value of +9‰, δ15N values of the NO2−released from RDX ranged from −7‰ to +2‰ during aerobic b...
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ABSTRACT
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In situ bioaugmentation with aerobic hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)-degrading bacteria is being considered for treatment of explosives-contaminated groundwater at Umatilla Chemical Depot, Oregon (UMCD). Two forced-gradient... more
In situ bioaugmentation with aerobic hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)-degrading bacteria is being considered for treatment of explosives-contaminated groundwater at Umatilla Chemical Depot, Oregon (UMCD). Two forced-gradient bacterial transport tests of site groundwater containing chloride or bromide tracer and either a mixed culture of Gordonia sp. KTR9 (xplA (+)Km(R)), Rhodococcus jostii RHA1 (pGKT2 transconjugant; xplA (+)Km(R)) and Pseudomonas fluorescens I-C (xenB (+)), or a single culture of Gordonia sp. KTR9 (xplA (+); i.e. wild-type) were conducted at UMCD. Groundwater monitoring evaluated cell viability and migration in the injection well and downgradient monitoring wells. Enhanced degradation of RDX was not evaluated in these demonstrations. Quantitative PCR analysis of xplA, the kanamycin resistance gene (aph), and xenB indicated that the mixed culture was transported at least 3 m within 2 h of injection. During a subsequent field injection of bioaugmented groundwater, strain KTR9 (wild-type) migrated up to 23-m downgradient of the injection well within 3 days. Thus, the three RDX-degrading strains were effectively introduced and transported within the UMCD aquifer. This demonstration represents an innovative application of bioaugmentation to potentially enhance RDX biodegradation in aerobic aquifers.
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The influence of bio-treatment on the structure and properties of internal wall tiles was tested. Nepheline-dolomite body D-8 was used for the manufacturing of the tiles. At the stage in which the clays and nonplastics are blended in the... more
The influence of bio-treatment on the structure and properties of internal wall tiles was tested. Nepheline-dolomite body D-8 was used for the manufacturing of the tiles. At the stage in which the clays and nonplastics are blended in the mixing tank with the slip, a suspension of silicate bacteria was added. It was found that the most marked change begins after three days. Tables show the fluidity of the experimental and control slips and the relationship between the density of the pressed specimens and the pressing force. The viscosity of the slip with the addition of the electrolyte is much lower than the viscosity of the control slip. The introduction of biotechnology in the production of ceramic tiles for internal wall facing will reduce the fuel consumption by 8-10%, reduce the cost of installing rollers made from scarce steels, reduce the amount of loss, and increase the grading of the product.
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Treatment of MTBE-Contaminated Water in Fluidized Bed Bioreactor. [Journal of Environmental Engineering 128, 842 (2002)]. Simon Vainberg, A. Paul Togna, Paul M. Sutton, Robert J. Steffan. Abstract. Methyl tertiary-butyl ether ...
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The potential for bioaugmentation with aerobic explosive degrading bacteria to remediate hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) contaminated aquifers was demonstrated. Repacked aquifer sediment columns were used to examine the... more
The potential for bioaugmentation with aerobic explosive degrading bacteria to remediate hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) contaminated aquifers was demonstrated. Repacked aquifer sediment columns were used to examine the transport and RDX degradation capacity of the known RDX degrading bacterial strains Gordonia sp. KTR9 (modified with a kanamycin resistance gene) Pseudomonas fluorescens I-C, and a kanamycin resistant transconjugate Rhodococcus jostii RHA1 pGKT2:Km+. All three strains were transported through the columns and eluted ahead of the conservative bromide tracer, although the total breakthrough varied by strain. The introduced cells responded to biostimulation with fructose (18 mg L(-1), 0.1 mM) by degrading dissolved RDX (0.5 mg L(-1), 2.3 µM). The strains retained RDX-degrading activity for at least 6 months following periods of starvation when no fructose was supplied to the column. Post-experiment analysis of the soil indicated that the residual cells were distributed along the length of the column. When the strains were grown to densities relevant for field-scale application, the cells remained viable and able to degrade RDX for at least 3 months when stored at 4 °C. These results indicate that bioaugmentation may be a viable option for treating RDX in large dilute aerobic plumes.
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ABSTRACT MTBE is widely used as a gasoline additive, and it has become a common and persistent groundwater contaminant. We have developed both in situ and ex situ bioremediation technologies for treating MTBE-contaminated groundwater. The... more
ABSTRACT MTBE is widely used as a gasoline additive, and it has become a common and persistent groundwater contaminant. We have developed both in situ and ex situ bioremediation technologies for treating MTBE-contaminated groundwater. The in situ approach relies on stimulating the growth and activity of propane-oxidizing bacteria that co-metabolically degrade MTBE, and the ex situ technologies rely on the use of engineered bioreactors and a novel bacterium that grows on MTBE as a sole carbon source.In earlier work, we demonstrated that propane-oxidizing bacteria can mineralize MTBE to CO2 after growth on propane (Steffan et al., 1997). Consequently, propane injection can be used to promote MTBE biodegradation by indigenous microorganisms in MTBE-contaminated aquifers, or to maintain the activity of exogenous propane-oxidizers used as seed cultures. To evaluate in situ propane biostimulation, laboratory treatability studies were conducted using aquifer material collected at sites in New Jersey and California. In microcosms from the California site, MTBE was degraded in samples amended with propane or propane and nutrients (nitrogen and phosphorous). Degradation (initial MTBE concentration ∼ 8 mg/L) was observed after a limited lag period of 10 to 20 days. In the samples from New Jersey, MTBE was not degraded in response to propane addition alone, but the oxygenate was degraded in samples inoculated with a culture of the propane-oxidizing bacterium ENV425.For ex situ treatment of MTBE, two 85-L membrane bioreactors (MBRs) were seeded with a bacterial strain recently isolated at Envirogen. This strain, designated Hydrogenophaga flava ENV735 (ENV735) grows on MTBE as a carbon source. The reactors were operated for several months with influent feeds of MTBE (1000 mg/L) in water, or MTBE (2000 mg/L) and BTEX (30 ppm) in water. For each reactor, the average effluent MTBE concentration was ∼100 μg/L during normal operation, and BTEX was below detection limits in the effluent.
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Treatment of MTBE-Contaminated Water in Fluidized Bed Bioreactor. [Journal of Environmental Engineering 128, 842 (2002)]. Simon Vainberg, A. Paul Togna, Paul M. Sutton, Robert J. Steffan. Abstract. Methyl tertiary-butyl ether ...
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A bacterium designated Pseudonocardia sp. strain ENV478 was isolated by enrichment culturing on tetrahydrofuran (THF) and was screened to determine its ability to degrade a range of ether pollutants. After growth on THF, strain ENV478... more
A bacterium designated Pseudonocardia sp. strain ENV478 was isolated by enrichment culturing on tetrahydrofuran (THF) and was screened to determine its ability to degrade a range of ether pollutants. After growth on THF, strain ENV478 degraded THF (63 mg/h/g total suspended solids [TSS]), 1,4-dioxane (21 mg/h/g TSS), 1,3-dioxolane (19 mg/h/g TSS), bis-2-chloroethylether (BCEE) (12 mg/h/g TSS), and methyl tert-butyl ether (MTBE) (9.1 mg/h/g TSS). Although the highest rates of 1,4-dioxane degradation occurred after growth on THF, strain ENV478 also degraded 1,4-dioxane after growth on sucrose, lactate, yeast extract, 2-propanol, and propane, indicating that there was some level of constitutive degradative activity. The BCEE degradation rates were about threefold higher after growth on propane (32 mg/h/g TSS) than after growth on THF, and MTBE degradation resulted in accumulation of tert-butyl alcohol. Degradation of 1,4-dioxane resulted in accumulation of 2-hydroxyethoxyacetic acid (2...
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Biodegradation of methyl tert-butyl ether (MTBE) by the hydrogen-oxidizing bacterium Hydrogenophaga flavaENV735 was evaluated. ENV735 grew slowly on MTBE ortert-butyl alcohol (TBA) as sole sources of carbon and energy, but growth on these... more
Biodegradation of methyl tert-butyl ether (MTBE) by the hydrogen-oxidizing bacterium Hydrogenophaga flavaENV735 was evaluated. ENV735 grew slowly on MTBE ortert-butyl alcohol (TBA) as sole sources of carbon and energy, but growth on these substrates was greatly enhanced by the addition of a small amount of yeast extract. The addition of H2 did not enhance or diminish MTBE degradation by the strain, and MTBE was only poorly degraded or not degraded by type strains of Hydrogenophaga or hydrogen-oxidizing enrichment cultures, respectively. MTBE degradation activity was constitutively expressed in ENV735 and was not greatly affected by formaldehyde, carbon monoxide, allyl thiourea, or acetylene. MTBE degradation was inhibited by 1-amino benzotriazole and butadiene monoepoxide. TBA degradation was inducible by TBA and was inhibited by formaldehyde at concentrations of >0.24 mM and by acetylene but not by the other inhibitors tested. These results demonstrate that separate, independent...
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Chlorinated solvents such as perchloroethylene (PCE) and trichloroethylene (TCE) continue to be significant groundwater contaminants throughout the USA. In many cases efficient bioremediation of aquifers contaminated with these chemicals... more
Chlorinated solvents such as perchloroethylene (PCE) and trichloroethylene (TCE) continue to be significant groundwater contaminants throughout the USA. In many cases efficient bioremediation of aquifers contaminated with these chemicals requires the addition of exogenous microorganisms, specifically members of the genus Dehalococcoides (DHC). This process is referred to as bioaugmentation. In this study a fed-batch fermentation process was developed for producing large volumes (to 3,200 L) of DHC-containing consortia suitable for treating contaminated aquifers. Three consortia enriched from three different sites were grown anaerobically with sodium lactate as an electron donor and PCE or TCE as an electron acceptor. DHC titers in excess of 10(11) DHC/L could be reproducibly obtained at all scales tested and with all three of the enrichment cultures. The mean specific DHC growth rate for culture SDC-9 was 0.036 +/- 0.005 (standard error, SE)/h with a calculated mean doubling time of 19.3 +/- 2.7 (SE) h. Finished cultures could be concentrated approximately tenfold by membrane filtration and stored refrigerated (4 degrees C) for more that 40 days without measurable loss of activity. Dehalogenation of PCE by the fermented cultures was affected by pH with no measurable activity at pH &amp;amp;amp;amp;amp;amp;lt;5.0.