Anaerobic O-demethylases are inducible multicomponent enzymes which mediate the cleavage of the ether bond of phenyl methyl ethers and the transfer of the methyl group to tetrahydrofolate. The genes of all components (methyltransferases I and II, CP, and activating enzyme [AE]) of the vanillate- and veratrol-O-demethylases of Acetobacterium dehalogenans ...
PubMed Central
Members of the genus Anaeromyxobacter are versatile, facultative microaerophilic myxobacteria isolated from soils, aquifers and freshwater sediments. Anaeromyxobacter spp. grow with nitrate as electron acceptor, which is reduced via nitrite to ammonia. Interestingly, the analysis of the Anaeromyxo...
Technology Transfer Automated Retrieval System (TEKTRAN)
Acetogenic bacteria grow by the oxidation of various substrates coupled to the reduction of carbon dioxide (acetogenesis) or other electron acceptors but the mechanisms of energy conservation are still enigmatic. Here, we report the presence of a rnf gene cluster rnfCDGEAB in Acetobacterium woodii that is speculated to encode a novel, energy-conserving ...
PubMed
Anaeromyxobacter dehalogenans is a microaerophilic member of the delta-proteobacteria which is able to utilize a wide range of electron acceptors, including halogenated phenols, U(VI), Fe(III), nitrate, nitrite, oxygen and fumarate. To date, the knowledge regarding general metabolic activities of this ecologically relevant bacterium is limited. Here, we present a first ...
Anaeromyxobacter dehalogenans strain 2CP-C is a versaphilic delta-Proteobacterium distributed throughout many diverse soil and sediment environments. 16S rRNA gene phylogenetic analysis groups A. dehalogenans together with the myxobacteria, which have distinguishing characteristics including strictly aerobic metabolism, sporulation, ...
Great interest has emerged in biological CO?-fixing processes in the context of current climate change discussions. One example for such a process is the hydrogenotrophic production of acetic acid by anaerobic microorganisms. Acetogenic microorganisms make use of carbon dioxide in the presence of hydrogen to produce acetic acid and biomass. In order to establish a process for the hydrogenotrophic ...
A psychrotolerant, obligate anaerobic, acetogenic bacterium designated strain SyrA5 was isolated from black anoxic sediment of a brackish fjord. Cells were Gram-positive, non-sporeforming rods. The isolate utilized H(2)/CO(2), CO, fructose, glucose, ethanol, ethylene glycol, glycerol, pyruvate, lactate, betaine and the methyl-groups of several methoxylated benzoic derivatives such as syringate, ...
The catabolism of methanol, formate, or carbon monoxide to acetate or butyrate or both was examined in two acetogenic bacteria. Butyribacterium methylotrophicum simultaneously transformed methanol and formate mainly to butyrate with concomitant H2 and CO2 production and consumption. In contrast, methanol plus CO was primarily converted to acetate, and only slight amounts of CO2 were produced. In ...
An oxygen-labile carbon monoxide dehydrogenase was purified to at least 98% homogeneity from fructose-grown cells of Acetobacterium woodii. Gel filtration and electrophoresis experiments gave molecular weights of 480,000 and 153,000, respectively, of the active enzyme. The molecular weights for the subunits are 80,000 and 68,000; the subunits occur in equal proportion. The ...
The anaerobic acetogenic bacterium Acetobacterium woodii couples caffeate reduction with electrons derived from hydrogen to the synthesis of ATP by a chemiosmotic mechanism with sodium ions as coupling ions, a process referred to as caffeate respiration. We addressed the nature of the hitherto unknown enzymatic activities involved in this process and their cellular ...
We examined the relative roles of acetogenic and sulfate-reducing bacteria in H2 consumption in a previously characterized subsurface sandstone ecosystem. Enrichment cultures originally inoculated with ground sandstone material obtained from a Cretaceous formation in central New Mexico were grown with hydrogen in a mineral medium supplemented with 0.02% yeast extract. ...
... from banded iron-formations in the Hamersley Group of Western Australia ... from CO2 and H2 during autotrophic growth of Acetobacterium woodii at 30 ...
NASA Website
Abstract: In samples of the Julia Creek and Condor oil shales (Australia, ... from CO2 and H2 during autotrophic growth of Acetobacterium woodii at 30 ...
... from CO2 and H2 during autotrophic growth of Acetobacterium woodii at 30 ... Abstract: In samples of the Julia Creek and Condor oil shales (Australia, ...
... from CO2 and H2 during autotrophic growth of Acetobacterium woodii at 30 ... from banded iron-formations in the Hamersley Group of Western Australia ...
A new genus of fastidiously anaerobic bacteria which produce a homoacetic fermentation is described. Cells are gram-positive, oval-shaped, short rods which are actively motile by means of one or two subterminal flagella. Hydrogen is oxidized, and carbon dioxide is reduced to acetic acid. Organic substrates which are fermented in a mineral medium include frutose, glucose, lactate, glycerate, and ...
Energy Citations Database
Members of the genus Anaeromyxobacter are well known for their versatile respiratory capabilities, including reductive dehalogenation of phenolic compounds. The widespread distribution of Anaeromyxobacter spp. in the environment suggests their potential significance in biogeochemical cycling includi...
Efficient host-vector systems have been developed for the versatile, strictly anaerobic, halo- and fumarate-respiring gram-positive bacterium Desulfitobacterium dehalogenans. An electroporation-based transformation procedure resulting in approximately 103 to 104 transformants per ?g of the cloning vector pIL253 was developed and ...
Microbiological reduction and immobilization of U(VI) and Tc(VII) has been proposed as a strategy for remediating radionuclide-contaminated environments. Numerous studies focusing on the reduction kinetics and speciation of these metals have been carried ...
National Technical Information Service (NTIS)
Ten years after reports on the existence of anaerobic dehalogenation of polychlorinated biphenyls (PCBs) in sediment slurries, the authors report here on the rapid reductive dehalogenation of para-hydroxylated PCBs (HO-PCBs), the excreted main metabolites of PCB in mammals, which can exhibit estrogenic and antiestrogenic activities in humans. The anaerobic bacterium Desulfitobacterium ...
Reserved. Uranium(VI) Reduction by Anaeromyxobacter dehalogenans Strain 2CP-C Qingzhong Wu,1 Robert A encountered at uranium-impacted sites, the metabolic versatility makes Anaeromyxobacter dehalogenans(VI) reduction and immobilization. Uranium is one of the most abundant radionuclides found in soils, sediments
E-print Network
We evaluated the microbial communities in acetate-rich production waters from separators of a high-temperature gas-petroleum reservoir in Higashi-Niigata, Japan. Bacterial and archaeal 16S rRNA gene libraries constructed from these waters were dominated by Acetobacterium-, Methanofollis-, and Methanosarcina-related sequences. The libraries constructed from enrichment cultures ...
Previous studies have demonstrated that metal-reducing microorganisms can effectively promote the precipitation and removal of uranium from contaminated groundwater. Microbial communities were stimulated in the acidic subsurface by pH neutralization and addition of an electron donor to wells. In single-well push-pull tests at a number of treated sites, nitrate, Fe(III), and uranium were ...
Selenium oxyanions are toxic to living organisms at excessive levels. The accumulation of selenium in certain environments requires the development of efficient detoxification processes. In this study, we demonstrated the ability of two Anaeromyxobacter dehalogenans strains to readily convert toxic Se(IV) to less toxic insoluble Se(0), as confirmed by energy-dispersive X-ray ...
Anaeromyxobacter dehalogenans strain 2CP-C reduces U(VI) and Tc(VII) to U(IV)O(2(s)) (uraninite) and Tc(IV)O(2(S)) respectively. Kinetic studies with resting cells revealed that U(VI) or Tc(VII) reduction rates using H(2) as electron donor exceeded those observed in acetate-amended incubations. The reduction of U(VI) by A. dehalogenans 2CP-C resulted in ...
Reduction of U(VI) to U(IV) as the result of direct or indirect microbial activity is currently being explored for in situ remediation of subsurface U plumes, under the assumption that U(IV) solubility is controlled by the low-solubility mineral uraninite (U(IV)-dioxide). However, recent characterizations of U in sediments from biostimulated field sites, as well as laboratory U(VI) bioreduction ...
The majority of bacteria elude culture in the laboratory. A metagenomic approach provides culture-independent access to the gene pool of the whole bacterial community. A metagenomic library was constructed from an industrial effluent treatment plant sludge containing about 1.25 Gb of microbial community DNA. Two arsenic-resistant clones were selected from the metagenomic library. Clones MT3 and ...
Desulfomonile tiedjei and Desulfitobacterium dehalogenans were chosen as model bacteria to demonstrate the introduction of an anaerobic microbia reductive dechlorination activity into nonsterile soil slurry microcosms by inoculation. De novo 3-chlorobenzoate dechlorination activity was established with the bacterium D. tiedjei in microcosms normally devoid of this ...
The capability of Anaeromyxobacter dehalogenans to reduce Se(IV) to Se(0) as a detoxification mechanism suggests a potential role of these ecologically important microorganisms in the biogeochemical cycling of selenium and the control of selenium contamination. However, the reduction of Se(IV) by the energetically versatile A. dehalogenans could be ...
BackgroundMicroorganisms inhabiting subterranean oil fields have recently attracted much attention. Since intact groundwater can easily be obtained from the bottom of underground oil-storage cavities without contamination by surface water, studies on such oil-storage cavities are expected to provide valuable information to understand microbial ecology of subterranean oil fields.ResultsDNA was ...
The bacterial diversity of a subsurface water sample collected from a gas storage aquifer in an Upper Jurassic calcareous formation was investigated by culture of microorganisms and construction of a 16S rRNA gene library. Both culture and molecular techniques showed that members of the phyla Firmicutes and class delta-proteobacteria dominated the bacterial community. The presence of ...
Microbiological reduction and immobilization of U(VI) and Tc(VII) has been proposed as a strategy for remediating radionuclide-contaminated environments. Numerous studies focusing on the reduction kinetics and speciation of these metals have been carried out using contaminated sediment samples, microbial consortia, and pure bacterial cultures. While previous work with model organisms has ...
DOE Information Bridge
Triethanolamine (TEA) is converted into acetate and ammonia by a strictly anaerobic, gram-positive Acetobacterium strain LuTria3. Fermentation experiments with resting cell suspensions and specifically deuterated substrates indicate that in the acetate molecule the carboxylate and the methyl groups correspond to the alcoholic function and to its adjacent methylene group, ...
Anaerobic microbial processes have not been thoroughly studied in agricultural soils. Yet, anaerobic conditions may significantly impact agrochemical fate, nutrient cycling, and plant/seed-microbe interactions. As part of a broader weed ecology/weed management experimental program we have selected...
Recent findings suggest that Anaeromyxobacter populations play relevant roles in metal and radionuclide reduction and immobilization at contaminated DOE sites. This research effort will characterize Anaeromyxobacter dehalogenans strain 2CP-C as well as other Anaeromyxobacter isolates in hand, and assess their contribution towards metal detoxification and plume stabilization ...
Versaphilic Anaeromyxobacter dehalogenans strains implicated in hexavalent uranium reduction and immobilization are present in the fractured saprolite subsurface environment at the U.S. Department of Energy Integrated Field-Scale Subsurface Research Challenge (IFC) site near Oak Ridge, TN. To provide insight into the in situ distribution of Anaeromyxobacter strains in this ...
Anaeromyxobacter spp. respire soluble hexavalent uranium, U(VI), leading to the formation of insoluble U(IV), and are present at the uranium-contaminated Oak Ridge Integrated Field Research Challenge (IFC) site. Pilot-scale in situ bioreduction of U(VI) has been accomplished in area 3 of the Oak Ridge IFC site following biostimulation, but the susceptibility of the reduced material to oxidants ...
The stimulation of bacteria capable of reducing soluble U(VI) to sparingly soluble U(IV) is a promising approach for containing U(VI) plumes. Anaeromyxobacter dehalogenans is capable of mediating this activity; however, its ability to couple U(VI) reduction to growth has not been established. Monitoring the increase in 16S rRNA gene copy numbers using quantitative real-time ...
Anaeromyxobacter dehalogenans strain 2CP-C can rapidly reduce U(VI) or Tc(VII) to U(IV)O2(s) or Tc(IV)O2(S) using either acetate or H2 as an electron donor source. Kinetic studies reveal that the H2-driven reduction of either U(VI) or Tc(VII) is faster than the acetate-driven reduction. The sub-cellular localization of reduced UO2 is extracellular while TcO2 nanoparticles are ...
Growth of Acetobacterium woodii on fructose was stimulated by Na+; this stimulation was paralleled by a shift of the acetate-fructose ratio from 2.1 to 2.7. Growth on H2-CO2 or on methanol plus CO2 was strictly dependent on the presence of sodium ions in the medium. Acetate formation from formaldehyde plus H2-CO by resting cells required Na+, but from methanol plus H2-CO did ...
Acetobacterium woodii formed ethanol as a fermentation product in addition to acetate when the phosphate concentration of the medium was between 0.2 and 8.4 mM. Considerable amounts of alanine were also found (2 to 11 mM). Supplementation with phosphate caused a shift to acetate as the only end product. Ethanol could also serve as a substrate for A. woodii. The fermentation ...
Assay of O-demethylation in cell-free extracts of Acetobacterium woodii: we have shown that THF and ATP are necessary for enzyme activity and thus are probably reactants; apparent Km values were 0.65 mM for the methoxylated substrate, 0.27 mM for ATP, and 0.17 mM for DL-THF. The enzyme activity is present in the cytosol, rather than being membrane bound, and is sensitive to ...
Previous studies demonstrated growth of Anaeromyxobacter dehalogenans strain 2CP-C with acetate or hydrogen as the electron donor and Fe(III), nitrate, nitrite, fumarate, oxygen, or ortho-substituted halophenols as electron acceptors. In this study, we explored and characterized U(VI) reduction by strain 2CP-C. Cell suspensions of fumarate-grown 2CP-C cells reduced U(VI) to ...
Dehalobacter and �Dehalococcoides� spp. were previously shown to be involved in the biotransformation of 1,1,2-trichloroethane (1,1,2-TCA) and 1,2-dichloroethane (1,2-DCA) to ethene in a mixed anaerobic enrichment culture. Here we report the further enrichment and characterization of a Dehalobacter sp. from this mixed culture in coculture with an Acetobacterium sp. Through ...
Microorganisms in the nuclear waste repository environment may interact with plutonium through (i) sorption, (ii) intracellular accumulation, and (iii) transformation of chemical speciation. These interactions may retard or enhance the mobility of Pu by precipitation reactions, biocolloid formation, or production of more soluble species. Current and planned radioactive waste repository ...
NASA Astrophysics Data System (ADS)
Methanobacterium thermoautotrophicum has been reported to require nickel for growth and to contain high concentrations of a nickel tetrapyrrole designated factor F430. In this communication it is shown that all methanogenic bacteria investigated incorporated nickel during growth and also synthesized factor F430. This was also true for Methanobrevibacter smithii, which is dependent on acetate as a ...
Microorganisms in the nuclear waste repository environment may interact with plutonium through (1) sorption, (2) intracellular accumulation, and (3) transformation speciation. These interactions may retard or enhance the mobility of Pu by precipitation reactions, biocolloid formation, or production of more soluble species. Current and planned radioactive waste repository environments, such as deep ...
A microbiological process was established to harvest electricity from the carbon monoxide (CO). A CO fermenter was enriched with CO as the sole carbon source. The DGGE/DNA sequencing results showed that Acetobacterium spp. were enriched from the anaerobic digester fluid. After the fermenter was operated under continuous mode, the products were then continuously fed to the ...
We investigate the physiological requirements of available Anaeromyxobacter isolates, and assess their distribution and abundance in the environment, including DOE sites. The performers on this project include Frank Loeffler (PI), Robert Sanford (Co-PI), Qingzhong Wu (postdoc), Sara Henry (graduate student) and Cornell Gayle (undergraduate student). Year-1 efforts focused on method and tool ...
Variations in stable isotope ratios of redox sensitive elements are often used to understand redox processes occurring near the Earth's surface. Presented here are measurements of mass-dependent U isotope fractionation induced by U(VI) reduction by zerovalent iron (Fe0) and bacteria under controlled pH and HCO3- conditions. In abiotic experiments, Fe0 reduced U(VI), but the reaction failed to ...
Anaeromyxobacter dehalogenans strain 2CP-C has been shown to grow by coupling the oxidation of acetate to the reduction of ortho-substituted halophenols, oxygen, nitrate, nitrite, or fumarate. In this study, strain 2CP-C was also found to grow by coupling Fe(III) reduction to the oxidation of acetate, making it one of the few isolates capable of growth by both metal reduction ...
Five strains were isolated which form a physiologically and phylogenetically coherent group of chlororespiring microorganisms and represent the first taxon in the Myxobacteria capable of anaerobic growth. The strains were enriched and isolated from various soils and sediments based on their ability to grow using acetate as an electron donor and 2-chlorophenol (2-CPh) as an electron acceptor. They ...
Five anaerobic bacteria were tested for their abilities to transform tetrachloromethane so that information about enzymes involved in reductive dehalogenations of polychloromethanes could be obtained. Cultures of the sulfate reducer Desulfobacterium autotrophicum transformed some 80 {mu}M tetrachloromethane to trichloromethane and a small amount of dichloromethane in 18 days under conditions of ...
An NAD-dependent 5,10-methylenetetrahydrofolate dehydrogenase has been purified to homogeneity from autotrophically and heterotrophically grown cells of Acetobacterium woodii. The enzymes from the differently grown cells were indistinguishable by gel filtration and sodium dodecyl sulfate electrophoresis and have a final specific activity of 670 units mg-1. The enzyme is ...
Sodium lactate additions to a trichloroethene (TCE) residual source area in deep, fractured basalt at a U.S. Department of Energy site have resulted in the enrichment of the indigenous microbial community, the complete dechlorination of nearly all aqueous-phase TCE to ethene, and the continued depletion of the residual source since 1999. The bacterial and archaeal consortia in groundwater obtained ...
A bacterial consortium capable of sucrose degradation primarily to CH/sub 4/ and CO/sub 2/ was constructed, with acetate as the key methanogenic precursor. In addition, the effect of agar immobilization on the activity of the consortium was determined. The primary fermentative organism, Escherichia coli, produced acetate, formate, H/sub 2/, and CO/sub 2/ (known substrates for methanogens), as well ...
The objective of this study was to evaluate the effect of hydroxocobalamin (OH-Cbl) on transformation of high concentrations of carbon tetrachloride (CT) by Acetobacterium woodii. Complete transformation of 470 {micro}M CT was achieved by A. woodii within 2.5 days, when 10 {micro}M OH-Cbl was added along with 25.2 mM fructose. This was approximately 30 times faster than A. ...
The objective of this study was to evaluate the effect of hydroxocobalamin (OH-Cbl) on transformation of high concentrations of carbon tetrachloride (CT) by Acetobacterium woodii (ATCC 29683). Complete transformation of 470 ?M (72 mg/liter [aqueous]) CT was achieved by A. woodii within 2.5 days, when 10 ?M OH-Cbl was added along with 25.2 mM fructose. This was approximately 30 ...
Deep subseafloor sediments may contain depressurization-sensitive, anaerobic, piezophilic prokaryotes. To test this we developed the DeepIsoBUG system, which when coupled with the HYACINTH pressure-retaining drilling and core storage system and the PRESS core cutting and processing system, enables deep sediments to be handled without depressurization (up to 25 MPa) and anaerobic prokaryotic ...
Growth characteristics of Eubacterium limosum and Acetobacterium woodii during one-carbon-compound utilization were investigated. E. limosum RF grew with formate as the sole energy source. Formate also replaced a requirement for CO2 during growth with methanol. Growth with methanol required either rumen fluid, yeast extract, or acetate, but their effects were not additive. ...
Recent declines in sea grass distribution underscore the importance of understanding microbial community structure-function relationships in sea grass rhizospheres that might affect the viability of these plants. Phospholipid fatty acid analyses showed that sulfate-reducing bacteria and clostridia were enriched in sediments colonized by the sea grasses Halodule wrightii and Thalassia testudinum ...
The anaerobic acetogenic bacterium Acetobacterium woodii couples the reduction of caffeate with electrons derived from hydrogen to the synthesis of ATP by a chemiosmotic mechanism using sodium ions as coupling ions, but the enzymes involved remain to be established. Previously, the electron transfer flavoproteins EtfA and EtfB were found to be involved in caffeate respiration. ...
Resting cells of Desulfitobacterium dehalogenans JW/IU-DC1 grown with pyruvate and 3-chloro-4-hydroxy-phenylacetate (3-Cl-4-OHPA) as the electron acceptor and inducer of dehalogenation reductively ortho-dehalogenate pentachlorophenol (PCP); tetrachlorophenols (TeCPs); the trichlorophenols 2,3,4-TCP, 2,3,6-TCP, and 2,4,6-TCP; the dichlorophenols 2,3-DCP, 2,4-DCP, and 2,6-DCP; ...
Methylenetetrahydrofolate dehydrogenase is widely distributed and has been found in every cell type investigated. The NAD-specific enzyme has been purified to homogeneity from Clostridium formicoaceticum and the NADP-specific enzyme has been obtained from Clostridium thermoaceticum. Other sources of the NADP-specific enzyme are Streptococcus species, Escherichia coli, Clostridium cylindrosporum, ...
Linear alkyl ethoxylates (polyethylene glycol alkyl ethers) were fermented completely to methane and CO2 in enrichment cultures inoculated with anoxic sewage sludge. Long-chain fatty acids were released as intermediates. No degradation was found with polypropylene glycol and polypropylene glycol-containing surfactants. Two types of primary ethoxylate-degrading bacteria were isolated and ...
Microbial electrosynthesis, a process in which microorganisms use electrons derived from electrodes to reduce carbon dioxide to multicarbon, extracellular organic compounds, is a potential strategy for capturing electrical energy in carbon-carbon bonds of readily stored and easily distributed products, such as transportation fuels. To date, only one organism, the acetogen Sporomusa ovata, has been ...
Growth of Acetobacterium woodii and Clostridium sporogenes was studied in the presence of water-immiscible solvents. Nitrogen purging, vacuum distillation or distillation under nitrogen were all suitable as methods to remove oxygen from the solvents, since growth rates and yields of A. woodii were unaffected in the presence of tetradecane which had been degassed by these ...
The ability of hydrolytic products of coenzyme F420 to substitute for F420 in the hydrogenase and nicotinamide adenine dinucleotide phosphate-liniked hydrogenase systems of Methanobacterium strain M.o.H. was kinetically determined. The nicotinamide adenine dinucleotide phosphate-linked hydrogenase system was employed to quantitate the levels of F420 in a number of methanogenic bacteria as well as ...
Clostridium ljungdahlii is an anaerobic homoacetogen, able to ferment sugars, other organic compounds, or CO(2)/H(2) and synthesis gas (CO/H(2)). The latter feature makes it an interesting microbe for the biotech industry, as important bulk chemicals and proteins can be produced at the expense of CO(2), thus combining industrial needs with sustained reduction of CO and CO(2) in the atmosphere. ...
Clostridium ljungdahlii is an anaerobic homoacetogen, able to ferment sugars, other organic compounds, or CO2/H2 and synthesis gas (CO/H2). The latter feature makes it an interesting microbe for the biotech industry, as important bulk chemicals and proteins can be produced at the expense of CO2, thus ...
Homoacetogenic bacteria can catalyze the reductive synthesis of acetate from CO2 via the acetyl-CoA pathway. Besides this unifying property homoacetogenic bacteria constitute a metabolically and phylogenetically diverse bacteriological group. Therefore their environmental role is difficult to address. It has been recognized that in methanogenic environments homoacetogenic bacteria contribute to ...
The conversion of biomass-derived synthesis gas (or syngas in brief) into biofuels by microbial catalysts (such as Clostridium ljungdahlii, Clostridium autoethanogenum, Acetobacterium woodii, Clostridium carboxidivorans and Peptostreptococcus productus) has gained considerable attention as a promising alternative for biofuel production in the recent past. The utilization of ...
The nickel-containing CO dehydrogenases from Acetobacterium woodii and Clostridium thermoaceticum were studied by EPR spectroscopy in order to define the components involved in the EPR spectrum obtained by reaction of the enzymes with the substrate, CO. Using isotopic substitution techniques, these experiments unequivocally establish that a nickel-carbon species is involved in ...
The nickel-containing CO dehydrogenase from Acetobacterium woodii and Clostridium thermoaceticum were studied by EPR spectroscopy in order to define the components involved in the EPR spectrum obtained by reaction of the enzymes with the substrate, CO. Using isotopic substitution techniques, these experiments unequivocally establish that a nickel-carbon species is involved in ...
Resting cells of Desulfitobacterium dehalogenans JW/IU-DC1 growth with pyruvate and 3-chloro-4-hydroxyphenylacetate (3-Cl-4-OHPA) as the electron acceptor and inducer of dehalogenation reductively ortho-dehalogenate pentachlorophenol (PCP); tetrachlorophenols (TeCPs); the trichlorophenols 2,3,4-TCP, 2,3,6-TCP, and 2,4,6-TCP; the dichlorophenols 2,3-DCP, 2,4-DCP, and 2,6-DCP; ...
This study demonstrates the ability of Desulfitobacterium spp. to utilize aliphatic sulfonates as terminal electron acceptors (TEA) for growth. Isethionate (2-hydroxyethanesulfonate) reduction by Desulfitobacterium hafniense resulted in acetate as well as sulfide accumulation in accordance with the expectation that the carbon portion of isethionate was oxidized to acetate and the sulfur was ...
The synthesis and degradation of anthropogenic and natural organohalides are the basis of a global halogen cycle. Chlorinated hydroquinone metabolites (CHMs) synthesized by basidiomycete fungi and present in wetland and forest soil are constituents of that cycle. Anaerobic dehalogenating bacteria coexist with basidiomycete fungi in soils and sediments, but little is known about the fate of these ...
Methane produced in freshwater sediments, where acetate is the major substrate utilized by methanogenic bacteria, is commonly depleted in {sup 13}C. Variations in the carbon-isotopic composition of methane have been related to flows of acetate carbon to various fates within microbial communities. To examine these processes, the isotopic compositions of biogenic methane and its sedimentary sources ...
Microbiological analyses of sediment samples were conducted to explore potentials and limitations for bioremediation of field sites polluted with chlorinated ethenes. Intact sediment cores, collected by direct push probing from a 35-ha contaminated area, were analyzed in horizontal layers. Cultivation-independent PCR revealed Dehalococcoides to be the most abundant 16S rRNA gene phylotype with a ...
The demethylation of the algal osmolyte dimethylsulfoniopropionate (DMSP) to methylthiopropionate (MTPA) by (homo)acetogenic bacteria was studied. Five Eubacterium limosum strains (including the type strain), Sporomusa ovata DSM 2662T, Sporomusa sphaeroides DSM 2875T, and Acetobacterium woodii DSM 1030T were ...
Cellulytic bacteria, cellobiose fermentors, sulfate-reducing bacteria and methanogenic bacteria have been isolated from established anaerobic mesophilic and thermophilic cellulose-methane fermentations and these isolates, plus known laboratory strains, have been employed to partially reconstitute highly active cellulose fermentations. These mixed cultures will be utilized as model systems to study ...
Bacteria belonging to the genus Dehalococcoides play a key role in the complete detoxification of chloroethenes as these organisms are the only microbes known to be capable of dechlorination beyond dichloroethenes to vinyl chloride (VC) and ethene. However, Dehalococcoides strains usually grow slowly with a doubling time of 1 to 2 days and have complex nutritional requirements. Here we describe ...
DL-Tetrahydrofolate (THF) and ATP were necessary for the anaerobic O-demethylation of phenylmethylethers in cell extracts of the type strain (ATCC 29683) of the homoacetogen Acetobacterium woodii. The reactants for this enzymatic activity have not been previously demonstrated in any system, nor has the mediating enzyme been studied. An assay using reaction mixtures containing ...
A novel anaerobic consortium, named DehaloR^2, that performs rapid and complete reductive dechlorination of trichloroethene (TCE) to ethene is described. DehaloR^2 was developed from estuarine sediment from the Back River of the Chesapeake Bay and has been stably maintained in the laboratory for over 2�years. Initial sediment microcosms showed incomplete reduction of TCE to DCE with a ratio of ...
Biological sulfate reduction was studied in laboratory-scale gas-lift reactors. Synthesis gas (gas mixtures of H(2)/CO/CO(2)) was used as energy and carbon source. The required biomass retention was obtained by aggregation and immobilization on pumice particles. Special attention was paid to the effect of CO addition on the sulfate conversion rate, aggregation, and aggregate composition.Addition ...
The anaerobic acetogenic bacterium Acetobacterium woodii carries out a unique type of Na+-motive, anaerobic respiration with caffeate as electron acceptor, termed �caffeate respiration.� Central, and so far the only identified membrane-bound reaction in this respiration pathway, is a ferredoxin:NAD+ oxidoreductase (Fno) ...
Anaerobic O-demethylation (AOD) of phenylmethylethers is a process of both basic and applied significance. The aryl-O-methyl ethers are abundant in natural products, particularly as components of lignin. They are present as methoxylated lignin monomers in anaerobic environments and can be completely degraded there by mixed microbial populations. AOD is an essential early step in this process, and ...
