Aquifer microcosms were used to investigate the effect of stimulating denitrification on microbial population shifts and BTX degradation potential. Selective pressure for facultative denitrifiers was applied to a treatment set by feeding acetate and nitrate, and cycling electr...
EPA Science Inventory
During March the authors began the leaching of the extracted catalyst with denitrifying bacteria. The results are shown in the attached Figures. They found that the solvent has a great effect on the ability of the denitrifying bacteria to release the meta...
National Technical Information Service (NTIS)
Previous laboratory studies have shown that alkylbenzenes could be degraded under denitrifying conditions by indigenous subsurface microbial populations in a shallow water table aquifer at Traverse City (MI) that was contaminated with JP-4 jet fuel. The objective of these tests, was to evaluate the extent of BTEX biodegradation by acclimated and ...
Energy Citations Database
Little information is available regarding the landscape-scale distribution of microbial communities and its environmental determinants. Here we combined molecular approaches and geostatistical modeling to explore spatial patterns of the denitrifying community at large scales. The distribution of denitrifrying community was investigated over 107 sites in ...
NASA Astrophysics Data System (ADS)
The ability of diverse microbial species to concentrate uranium, cesium, and radium was examined. Saccharomyces cerevisiae, Pseudomonas aeruginosa, and a mixed culture of denitrifying bacteria accumulated uranium to 10 to 15% of the dry cell weight. Only ...
Two heterotrophic denitrifying bacteria, Paracoccus denitrificans and Pseudomonas denitrificans, have been shown to utilize nitric oxide (NO) as a terminal electron acceptor and succinate, yeast extract, and heat/alkali pretreated municipal sewage sludge as carbon and energy sources. Complete removal of NO (0.50%) from a feed gas sparged into the cultures was observed. It is ...
Groundwater was collected from a petroleum hydrocarbon contaminated site and characterized for microbial and physiochemical properties to assess the feasibility of enhanced natural attenuation. Results demonstrate the depletion of nitrate and dominance of denitrifying bacteria in the groundwater. Microcosm studies of amending nitrate and nutrients were ...
PubMed
This work evaluates the impact of the external resistance (electrical load) on the long-term performance of a microbial fuel cell (MFC) and demonstrates the real-time optimization of the external resistance. For this purpose, acetate-fed MFCs were operated at external resistances, which were above, below, or equal to the internal resistance of a ...
The aerobic sludge granules cultivated at high organic loading rates could effectively convert 100-700 mg l(-1) nitrite to nitrogen gas with 400 or 1,200 mg l(-1) dosed acetate. The denitrifying microbial community structure of the so-cultivated granules was investigated by 16S rRNA gene sequences and localized using fluorescence in situ hybridization ...
A mixed culture of denitrifying bacteria was evaluated for separating U from process wastewaters. The mixed culture was obtained as films on coal particles in an operating fluidized-bed bioreactor system. Biosorption of U by the mixed culture was rapid, reaching a saturation of approx. 0.14 g U per gram of dry cells. Two contacting devices were also evaluated. 4 figures. (DLC)
DOE Information Bridge
This patent describes a method of microbial enhanced oil recovery. It comprises the step of introducing, into a carbonate-containing rock formation that defines an anaerobic environment, denitrifying microorganisms, an aqueous liquid carrier and a nonoxygen electron accepter, such that the microorganism reduce the non-oxygen electron accepter in the ...
is licensed under a Creative Commons License. Biogeosciences nirS-containing denitrifier communities structural differences in the nirS-type denitrifying microbial commu- nities along the environmental fragment length polymorphism (T-RFLP) based on nirS as a functional marker gene for denitrification. nir
E-print Network
and Lovley 2005); sulfate-reducing bacteria (SRB) including Desulfur- omonas (Bond et al. 2002 respiration (Logan 2009). These include dissimilatory metal-reducing bacteria (DMRB) such as Geobacter (Bond) and Desulfobulbus (Holmes et al. 2004a); and nitrate-reducing bacteria (denitrifying bacteria (DNB)) including
This study studied the cultivation of granules from an expanded granular sludge bed reactor that simultaneously transforms sulfates, nitrates, and oxygen to elementary sulfur, nitrogen gas, and carbon dioxides, respectively. The living cells accumulate at the granule outer layers, as revealed by the multicolor staining and confocal laser scanning microscope technique. The ...
A mixed culture of denitrifying bacteria was evaluated for separating U from process wastewaters. The mixed culture was obtained as films on coal particles in an operating fluidized-bed bioreactor system. Biosorption of U by the mixed culture was rapid, r...
The utilization of monochlorobenzoate isomers (2-, 3- and 4-chlorobenzoate) by anaerobic microbial consortia in River Nile sediments was systematically evaluated under denitrifying, Fe-reducing, sulfidogenic and methanogenic conditions. Loss of all three chlorobenzoates was noted in denitrifying cultures; furthermore, the initial ...
The microbial community structure of anaerobic biological reactors was evaluated by using oligonucleotide probes complementary to conserved tracts of the 16S rRNAs of phylogenetically defined groups of methanogens. Phylogenetically defined groups of methanogens were quantified and visualized, respectively, by hybridization of 32P- and fluorescent-dye-labeled probes to the 16S ...
PubMed Central
The export of nitrogen from urban catchments is a global problem, and denitrifying bacteria in stream ecosystems are critical for reducing in-stream N. However, the environmental factors that control the composition of denitrifying communities in streams are not well understood. We determined whether denitrifying community composition ...
The acclimated, anaerobic microbial community is an efficient method for indole-containing wastewater treatment. However, our understanding of the diversity of indole-degrading communities is still limited. We investigated two anaerobic, indole-decomposing microbial communities under both denitrifying and sulfate-reducing conditions. ...
The development of an effective biotrickling filter (BF) system to inoculate a newly isolated strain of Pseudomonas putida SB1 for the effective treatment of nitric oxide (NO) is described. The experiments were carried out in a bench-scale BF under high concentrations of O(2) and NO in simulated flue gas. A method including alternating aeration in screening and rescreening based on the pH changes ...
BACKGROUND: Denitrification is a microbial process that has received considerable attention during the past decade since it can result in losses of added nitrogen fertilisers from agricultural soils. Paddy soil has been known to have strong denitrifying activity, but the denitrifying microorganisms responsible for fertilisers in paddy ...
Most denitrifiers produce nitrous oxide (N2O) instead of dinitrogen (N2) under aerobic conditions. We isolated and characterized novel aerobic denitrifiers that produce low levels of N2O under aerobic conditions. We monitored the denitrification activities of two of the isolates, strains ...
While there is ample evidence that microbial processes can exhibit large variations at a field scale, very little is known about the spatial distribution of the communities mediating these processes. To explore spatial patterns of size and activity of the denitrifying community, a functional guild involved in N-cycling, in a grassland field subjected to ...
The impact of different quinoid redox mediators on the simultaneous conversion of sulphide and nitrate in a denitrifying culture was evaluated. All quinones evaluated, including anthraquinone-2,6-disulphonate (AQDS), 2-hydroxy-1,4-naphthoquinone and 1,2-naphthoquinone-4-sulphonate (NQS) were reduced by sulphide under abiotic conditions. NQS showed the highest reduction rate by ...
Perchlorate is an emerging surface water and groundwater contaminant, and it is of concern because of its mobility in the environment and its inhibitory effect on thyroid function. Microbial fuel cells (MFCs) may be a suitable method for its treatment. We investigated a MFC with a denitrifying biocathode for perchlorate reduction and utilized the system to ...
The primary goal of this research is to further present understanding of the effect of mixed oxygen/nitrate electron acceptor conditions on the biodegradation of benzene, toluene, ethylbenzene, m-xylene, naphthalene, and phenanthrene. Specific objectives include: (1) identify subsurface microbial cultures with the ability to biodegrade aromatic hydrocarbons under aerobic and ...
Disclosed is a process by which a gas containing nitric oxide is contacted with an anaerobic microbial culture of denitrifying bacteria to effect the chemical reduction of the nitric oxide to elemental nitrogen. The process is particularly suited to the removal of nitric oxide from flue gas streams and gas streams from nitric acid plants. Thiobacillus ...
This study examined the microbial degradation of acenaphthene and naphthalene under denitrification conditions at soil-to-water ratios of 1:25 and 1:50 with soil containing approximately 10 sup 5 denitrifying organisms per gram of soil. Under nitrate-exce...
Detoxification of perchlorate by microbial communities under denitrifying conditions has been recently reported, although the identity of the mixed populations involved in perchlorate reduction is not well understood. In order to address this, the bacterial diversity of membrane ...
Microbial biomass, nitrifiers and denitrifiers in surface soil (0?10 cm) were quantified in a riparian zone restoration project at Coweeta, North Carolina, USA. Four treatments are included in this study: (1) a degraded (+N) riparian zone with continued compaction, vegetation rem...
There is ample evidence that microbial processes can exhibit large variations in activity on a field scale. However, very little is known about the spatial distribution of the microbial communities mediating these processes. Here we used geostatistical modelling to explore spatial patterns of size and activity of the denitrifying ...
The aim of this study was to compare structural differences in the nirS-type denitrifying microbial communities along the environmental gradients observed in the water column and coastal sediments of the Baltic Sea. To link community structure and environmental gradients, denitrifier communities were analyzed by terminal restriction ...
The aim of this study was to compare structural differences in the denitrifying microbial communities along the environmental gradients observed in the water column and coastal sediments of the Baltic Sea. To link community structure and environmental gradients, denitrifier communities were analyzed by terminal restriction fragment ...
This study investigates microbial population dynamics in granular sequencing batch reactors (GSBR). The experimental results of DGGE fingerprint of sludge demonstrated that the microbial community structure of sludge shifted significantly during granulation period and nutrient removal improvement period. After reactor performance and physical ...
Knowing spatial patterns of functional microbial guilds can increase our understanding of the relationships between microbial community ecology and ecosystem functions. Using geostatistical modeling to map spatial patterns, we explored the distribution of the community structure, size, and activity of one functional group in N cycling, the ...
Rice paddy soil has been shown to have strong denitrifying activity. However, the microbial populations responsible for nitrate respiration and denitrification have not been well characterized. In this study, we performed a clone library analysis of >1,000 clones of the nearly full-length 16S rRNA gene to characterize bacterial community structure in ...
Microbial N2O release during the course of thawing of soil was investigated in model experiment focusing on denitrification, since freeze-thaw has been shown to cause significant physical and biological changes in soil, including a surge of N2O and CO2. The origin of these is still controversially discussed. ...
Biotransformation of various chemical forms of uranium present in wastes, contaminated soils and materials by microorganisms under different process conditions such as aerobic and anaerobic (denitrifying, iron-reducing, fermentative, and sulfate-reducing) conditions will affect the solubility, bioavailability, and mobility of uranium in the natural environment. Fundamental ...
Considerable information has been accumulated on the toxicity of hydrazine to soil bacterial cultures and on the degradation of hydrazne by soil bacterial cultures. The activities of the autotrophic nitrifiers Nitrosomonas and Nitrobacter and of denitrifying bacteria, and the growth of Enterobacter cloacae, were all inhibited by hydrazine. An enzyme system has been found in ...
Microbial concentrations of denitrifiers, pseudomonads, and monoaromatic petroleum hydrocarbon (BTX) degraders were significantly higher (p < 0.1) in soil samples from the rhizosphere of poplar trees than in adjacent agricultural soils, and atrazine degraders were found only in one rhizosphere sample. The relative abundance of these phenotypes (as a ...
Zero-valent iron (Fe{sup 0})-based permeable reactive barrier treatment has been generating great interest for passive groundwater remediation, yet few studies have paid particular attention to the microbial activity and characteristics within and in the vicinity of the Fe{sup 0}-barrier matrix. The present study was undertaken to evaluate the microbial ...
Wetland mitigation is implemented to replace ecosystem functions provided by wetlands; however, restoration efforts frequently fail to establish equivalent levels of ecosystem services. Delivery of microbially mediated ecosystem functions, such as denitrification, is influenced by both the structure and activity of the microbial community. The objective of ...
Denitrifying microbial communities and denitrification in salt marsh sediments may be affected by many factors, including environmental conditions, nutrient availability, and levels of pollutants. The objective of this study was to examine how microbial community composition and denitrification enzyme activities (DEA) at a California ...
Nitrogen flux into the coastal environment via submarine groundwater discharge may be modulated by microbial processes such as denitrification, but the spatial scales at which microbial communities act and vary are not well understood. In this study, we examined the denitrifying community within the beach aquifer at Huntington Beach, ...
The effect of nitrate concentration on denitrification rate, microbial community and byproduct accumulation in sulfide-driven autotrophic denitrification, one of the dominant processes during anoxic marine sediment remediation, was investigated in this study. Microorganisms which were phylogenetically closely related with Sulfurimonas denitrificans of ?-Proteobacteria and ...
Oil reservoirs naturally contain inorganic and organic materials which may be exploited through simple mineral supplementation to support the growth of denitrifying microorganisms. The growth and metabolic products from the presence of these microorganisms will aid in the release of oil from the rock matrix and improve crude oil quality and oil field operations. These studies ...
Earthworms emit nitrous oxide (N2O) and dinitrogen (N2). It has been hypothesized that the in situ conditions of the earthworm gut activates ingested soil denitrifiers during gut passage and leads to these in vivo emissions (M. A. Horn, A. Schramm, and H. L. Drake, Appl. Environ. Microbiol. 69:1662-1669, 2003). This hypothesis ...
An anaerobic continuous-flow fixed-bed column reactor capable of degrading 3-chlorobenzoate (3-CBA) under denitrifying conditions was established, and its rate reached 2.26 mM d(-1). The denitrifying population completely degraded 3-CBA when supplied at 0.1-0.54 mM, but its activity was partly suppressed when 3-CBA was supplied at 0.89 mM. Nitrate was ...
The ammonifying activity of denitrifiers and their role in plant nutrition is discussed. Experiments
NASA Technical Reports Server (NTRS)
Contents of the journal include: Teleocidins, CFU-GM Colony Forming Substances of Microbial Origin (In English); Incorporation of (14C) Methanol and (14C) Bicarbonate by Hyphomicrobium sp. 53-49 under Various Growth Conditions: Aerobic, Denitrifying and A...
significantly to N2 effluxes in running waters exhibiting high rates of denitrification. Keywords Denitrification � Ebullition � Nitrogen � Bubbles � South Platte River Introduction Denitrification, the microbial of denitrifi- cation (Cle�ment et al. 2002; Sjodin et al. 1997). Mean annual rates of denitrification
A laboratory investigation was undertaken to determine the effect of microbe generated gas bubbles in controlled, saturated sediment columns utilizing a novel technique involving acoustic wave propagation. Specifically, the effect of denitrifying bacteria...
This patent describes a process for converting nitric oxide in a gas stream to elemental nitrogen. It comprises contacting the gas stream under anaerobic conditions with a slurry containing a denitrifying bacterium capable of converting the nitric oxide to elemental nitrogen and a culture medium containing an energy source for the bacterium and adapted to maintain the ...
We have defined critical areas for further study. These arise out of the basic nature of both the microorganisms and the nature of catalysts. Whereas other catalysts not employing Mo or W would probably be readily leached by T. ferrooxidans and denitrifie...
We have defined critical areas for further study. These arise out of the basic nature of both the microorganisms and the nature of catalysts. Whereas other catalysts not employing Mo or W would probably be readily leached by T. ferrooxidans and denitrifiers, those which contain these two metals require special attention and highly tolerant strains of T. ferrooxidans but not ...
The interactions of aniline with soil at an industrial spill site were investigated. Sorption of aniline to the soil was observed to occur through a two-step mechanism. The first step was an ion exchange process with the protonated amine serving as an organic cation. This step was influenced by solution pH and ionic composition. The second step was covalent bonding most likely with quinone ...
The variable biocatalyst density in a microbial fuel cell (MFC) anode biofilm is a unique feature of MFCs relative to other electrochemical systems, yet performance characterizations of MFCs typically involve analyses at electrochemically relevant time scales that are insufficient to account for these variable biocatalyst effects. This study investigated the electrochemical ...
The physiological and kinetic behavior of a denitrifying granular sludge exposed to different sulfide loading rates (55-295 mg/L d) were evaluated in a UASB reactor fed with acetate, ammonium and nitrate. At any sulfide loading rates, the consumption efficiencies of sulfide, acetate and ammonium were above 95%, while nitrate consumption efficiencies were around 62-72%. At the ...
During March the authors began the leaching of the extracted catalyst with denitrifying bacteria. The results are shown in the attached Figures. They found that the solvent has a great effect on the ability of the denitrifying bacteria to release the metals from the catalyst matrix, while the catalyst remains in whole particles. Subsequent to this they ...
Denitrifying sulfide removal (DSR) process simultaneously converts sulfide, nitrate, and chemical oxygen demand from industrial wastewaters to elemental sulfur, nitrogen gas, and carbon dioxide, respectively. This investigation utilizes a dilution-to-extinction approach at 10(-2) to 10(-6) dilutions to elucidate the correlation between the composition of the ...
Batch microcosm tests were performed with nonacclimated and acclimated aquifer material from Traverse City (MI) to assess the extent of biodegradation of radiolabeled benzene, toluene, ethylbenzene, and xylenes (BTEX), either as single substrates or in a mixture, by indigenous microorganisms under denitrifying conditions. For single substrate studies, the rates and extent of ...
The microbial capacity to degrade simple organic compounds with quaternary carbon atoms was demonstrated by enrichment and isolation of five denitrifying strains on dimethylmalonate as the sole electron donor and carbon source. Quantitative growth experiments showed a complete mineralization of dimethylmalonate. According to phylogenetic analysis of the ...
Recent technical advances for quantifying denitrification rates, denitrifier-N2O:N2 product ratios and linking these to the underpinning microbiology, have provided new insights into interactions between C and N processes, and flexibility of microbial function in response to changing environmental conditions and management. The availability of organic C ...
A denitrifying microbial consortium was enriched in an anoxically operated, methanol-fed sequencing batch reactor (SBR) fed with a mineral salts medium containing methanol as the sole carbon source and nitrate as the electron acceptor. The SBR was inoculated with sludge from a biological nutrient removal activated sludge plant exhibiting good ...
The quantification of denitrifying bacteria is a component in the further understanding of denitrification processes in the environment. Real-time PCR primers were designed to target two segments of the denitrifier population (cnorBP [Pseudomonas mandelii and closely related strains] and cnorBB [Bosea, ...
This study investigated operational factors influencing the removal of steroid estrogens and nonylphenolic compounds in two sewage treatment works, one a nitrifying/denitrifying activated sludge plant and the other a nitrifying/denitrifying activated sludge plant with phosphorus removal. Removal efficiencies of >90% for steroid estrogens and for longer ...
A geostatistical approach using replicated grassland sites (10 m � 10 m) was applied to investigate the influence of grassland management, i.e. unfertilized pastures and fertilized mown meadows representing low and high land-use intensity (LUI), on soil biogeochemical properties and spatial distributions of ammonia-oxidizing and denitrifying microorganisms in soil. Spatial ...
Although it is widely believed that horizontal patchiness exists in microbial sediment communities, determining the extent of variability or the particular members of the bacterial community which account for the observed differences among sites at various scales has not been routinely demonstrated. In this study, horizontal heterogeneity was examined in time and space for ...
Complete removal of plants and soil to exposed bedrock, in order to eradicate the Hole-in-the-Donut (HID) region of the Everglades National Park, FL, of exotic invasive plants, presented the opportunity to monitor the redevelopment of soil and the associated microbial communities along a short-term restoration chronosequence. Sampling plots were established for sites restored ...
Nonylphenol (NP) is an endocrine disruptor present as a pollutant in river sediment. Biodegradation of NP can reduce its toxicological risk. As sediments are mainly anaerobic, degradation of linear (4-n-NP) and branched nonylphenol (tNP) was studied under methanogenic, sulphate reducing and denitrifying conditions in NP polluted river sediment. Anaerobic bioconversion was ...
Due to its high usage, mobility, and recalcitrant nature, atrazine is a common groundwater contaminant. Moreover, groundwaters that are contaminated with atrazine often contain nitrate as well. Nitrate interferes with the biological degradation of atrazine and makes it more difficult to use in situ biological methods to remediate atrazine contaminated groundwater. To solve this problem we used two ...
Nitrification and denitrification are key steps in nitrogen (N) cycling. The coupling of these processes, which affects the flow of N in ecosystems, requires close interaction of nitrifying and denitrifying microorganisms, both spatially and temporally. The diversity, temporal and spatial variations in the microbial communities affecting these processes ...
The ability of diverse microbial species to concentrate uranium, cesium, and radium was examined. Saccharomyces cerevisiae, Pseudomonas aeruginosa, and a mixed culture of denitrifying bacteria accumulated uranium to 10 to 15% of the dry cell weight. Only a fraction of the cells in a given population had visible uranium deposits in electron micrographs. ...
Microbial communities in the biological filter and waste sludge compartments of a marine recirculating aquaculture system were examined to determine the presence and activity of anaerobic ammonium-oxidizing (anammox) bacteria. Community DNA was extracted from aerobic and anaerobic fixed-film biofilters and the anaerobic sludge waste collection tank and was analyzed by ...
In this study, a lab scale EGSB reactor was operated for 400 days to investigate the influence of temperature-decrease on the microbial characteristic of retained sludge. The EGSB reactor was started-up at 15 degrees C seeding with 20 degrees C-grown granular sludge. The influent COD of synthetic wastewater was set at 0.6-0.8 gCOD/L. The process-temperature was stepwise ...
A field-scale manipulation experiment conducted for 16 years in a Norway spruce forest at Solling, Central Germany, was used to follow the long-term response of total soil bacteria, nitrate reducers and denitrifiers under conditions of reduced N deposition. N was experimentally removed from throughfall by a roof construction ('clean rain plot'). We used substrate-induced ...
The acetate-utilizing microbial consortium in a full-scale activated sludge process was investigated without prior enrichment using stable isotope probing (SIP). [13C]acetate was used in SIP to label the DNA of the denitrifiers. The [13C]DNA fraction that was extracted was subjected to a full-cycle rRNA ...
Denitrification in the ocean is a major sink for fixed nitrogen in the global N budget, but the process is geographically restricted to a few oceanic regions, including three oceanic oxygen minimum zones (OMZ) and hemipelagic sediments worldwide. Here, we describe the diversity and community composition of microbes responsible for denitrification in the OMZ using polymerase chain reaction, ...
Anaerobic ammonium oxidation (anammox) and denitrification are two main microbial processes capable of removing fixed nitrogen by conversion into a gaseous species. Both microbial processes are known to occur in anoxic estuarine sediments and are capable of remediating excess nitrogen loadings from anthropogenic activities. In order to understand the ...
The microbial community (bacterial, archaeal, and fungi) and eight genes involved in the nitrogen biogeochemical cycle (nifH, nitrogen fixation; bacterial and archaeal amoA, ammonia oxidation; narG, nitrate reduction; nirS, nirK, nitrite reduction; norB, nitric oxide reduction; and nosZ, nitrous oxide reduction) were quantitatively assessed in this study, via real-time PCR ...
Microbial fuel cells (MFCs) have applications other than electricity production, including the capacity to power desirable reactions in the cathode chamber. However, current knowledge of the microbial ecology and physiology of biocathodes is minimal, and as a result more research dedicated to understanding the microbial communities ...
