Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| oxygen-limited autotrophic nitrification/denitrification by ammonia oxidisers enables upward motion towards more favourable conditions. | the hypothesis is formulated that in case of oxygen limitation in the sediment, nitrifiers switch from nitrification to oxygen-limited autotrophic nitrification-denitrification (oland) in order to survive and maintain activity. during oland, ammonium is oxidised using nitrite as e-acceptor to form dinitrogen gas. as an additional advantage they benefit from the gaseous n(2) formed as a means of transport. in this way, the nitrifiers can move out of the sediment and rise through the water column ... | 2002 | 12172626 |
| cooxidation of naphthalene and other polycyclic aromatic hydrocarbons by the nitrifying bacterium, nitrosomonas europaea. | the soil nitrifying bacterium nitrosomonas europaea has shown the ability to transform cometabolically naphthalene as well as other 2- and 3-ringed polycyclic aromatic hydrocarbons (pahs) to more oxidized products. all of the observed enzymatic reactions were inhibited by acetylene, a selective inhibitor of ammonia monooxygenase (amo). a strong inhibitory effect of naphthalene on ammonia oxidation by n. europaea was observed. naphthalene was readily oxidized by n. europaea and 2-naphthol was det ... | 2002 | 12713129 |
| intestinal urea metabolism: could the bacteria involved in nitrogen cycle lead to reutilization of intestinal urea nitrogen in uremic rabbits? | we aimed to evaluate the effect of bacteria involved in the nitrogen cycle on the reutilization of intestinal urea nitrogen in uremic rabbits. new zealand white rabbits were made uremic via bilateral nephrectomy. study and control rabbits were given live and heat-inactivated bacteria through their jejunostomies. after they were injected with 99mtc biurea intravenously, serial serum and stool levels of labeled nitrogen were assessed by instant thin-layer chromatography, and the change in the labe ... | 2002 | 12026184 |
| influence of different cultivars on populations of ammonia-oxidizing bacteria in the root environment of rice. | comparisons of the activities and diversities of ammonia-oxidizing bacteria (aob) in the root environment of different cultivars of rice (oryza sativa l.) indicated marked differences despite identical environmental conditions during growth. gross nitrification rates obtained by the 15n dilution technique were significantly higher in a modern variety, ir63087-1-17, than in two traditional varieties. phylogenetic analysis based on the ammonium monooxygenase gene (amoa) identified strains related ... | 2002 | 12039768 |
| evolution of sucrose synthesis. | cyanobacteria and proteobacteria (purple bacteria) are the only prokaryotes known to synthesize sucrose (suc). suc-p synthase, suc-phosphatase (spp), and suc synthase activities have previously been detected in several cyanobacteria, and genes coding for suc-p synthase (sps) and suc synthase (sus) have been cloned from synechocystis sp. pcc 6803 and anabaena (nostoc) spp., respectively. an open reading frame in the synechocystis genome encodes a predicted 27-kd polypeptide that shows homology to ... | 2002 | 11950997 |
| evaluation of non-cyanobacterial genome sequences for occurrence of genes encoding proteins homologous to cyanophycin synthetase and cloning of an active cyanophycin synthetase from acinetobacter sp. strain dsm 587. | all publicly accessible microbial genome databases were searched for the occurrence of genes encoding proteins homologous to the cyanophycin synthetase (cpha) of synechocystis sp. strain pcc 6803 in order to reveal the capability of microorganisms not belonging to the cyanobacteria to synthesize cyanophycin. among 65 genome sequences, genes homologous to cpha were found in acinetobacter sp. strain adp1 (encoding a protein homologous to cpha with 40% amino acid identity), bordetella bronchiseptic ... | 2002 | 11976746 |
| denaturing gradient gel electrophoresis (dgge) approaches to study the diversity of ammonia-oxidizing bacteria. | denaturing gradient gel electrophoresis (dgge) of pcr amplicons of the ammonia monooxygenase gene (amoa) was developed and employed to investigate the diversity of ammonia-oxidizing bacteria (aob) in four different habitats. the results were compared to dgge of pcr-amplified partial 16s rdna sequences made with primers specific for ammonia-oxidizing bacteria. potential problems, such as primer degeneracy and multiple gene copies of the amoa gene, were investigated to evaluate and minimize their ... | 2002 | 11997169 |
| grassland management regimens reduce small-scale heterogeneity and species diversity of beta-proteobacterial ammonia pxidizer populations. | the impact of soil management practices on ammonia oxidizer diversity and spatial heterogeneity was determined in improved (addition of n fertilizer), unimproved (no additions), and semi-improved (intermediate management) grassland pastures at the sourhope research station in scotland. ammonia oxidizer diversity within each grassland soil was assessed by pcr amplification of microbial community dna with both ammonia oxidizer-specific, 16s rrna gene (rdna) and functional, amoa, gene primers. pcr ... | 2002 | 11772604 |
| isolation and characterization of cbbl and cbbs genes encoding form i ribulose-1,5-bisphosphate carboxylase/oxygenase large and small subunits in nitrosomonas sp. strain eni-11. | the cbbl and cbbs genes encoding form i ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) large and small subunits in the ammonia-oxidizing bacterium nitrosomonas sp. strain eni-11 were cloned and sequenced. the deduced gene products, cbbl and cbbs, had 93 and 87% identity with thiobacillus intermedius cbbl and nitrobacter winogradskyi cbbs, respectively. expression of cbbl and cbbs in escherichia coli led to the detection of rubisco activity in the presence of 0.1 mm isopropyl-beta-d-th ... | 2002 | 12005060 |
| nitrosocyanin, a red cupredoxin-like protein from nitrosomonas europaea. | nitrosocyanin (nc), a soluble, red cu protein isolated from the ammonia-oxidizing autotrophic bacterium nitrosomonas europaea, is shown to be a homo-oligomer of 12 kda cu-containing monomers. oligonucleotides based on the amino acid sequence of the n-terminus and of the c-terminal tryptic peptide were used to sequence the gene by pcr. the translated protein sequence was significantly homologous with the mononuclear cupredoxins such as plastocyanin, azurin, or rusticyanin, the type 1 copper-bindi ... | 2002 | 11827513 |
| nitrite as a stimulus for ammonia-starved nitrosomonas europaea. | ammonia-starved cells of nitrosomonas europaea are able to preserve a high level of ammonia-oxidizing activity in the absence of ammonium. however, when the nitrite-oxidizing cells that form part of the natural nitrifying community do not keep pace with the ammonia-oxidizing cells, nitrite accumulates and may subsequently inhibit ammonia oxidation. the maintenance of a high ammonia-oxidizing capacity during starvation is then nullified. in this study we demonstrated that cells of n. europaea sta ... | 2002 | 11872501 |
| in situ characterization of nitrifiers in an activated sludge plant: detection of nitrobacter spp. | the purpose of this work was to investigate microbial ecology of nitrifiers at the genus level in a typical full-scale activated sludge plant. | 2002 | 12174041 |
| ammonia- and nitrite-oxidizing bacterial communities in a pilot-scale chloraminated drinking water distribution system. | nitrification in drinking water distribution systems is a common operational problem for many utilities that use chloramines for secondary disinfection. the diversity of ammonia-oxidizing bacteria (aob) and nitrite-oxidizing bacteria (nob) in the distribution systems of a pilot-scale chloraminated drinking water treatment system was characterized using terminal restriction fragment length polymorphism (t-rflp) analysis and 16s rrna gene (ribosomal dna [rdna]) cloning and sequencing. for ammonia ... | 2002 | 11772611 |
| the ribulose-1,5-bisphosphate carboxylase/oxygenase gene cluster of methylococcus capsulatus (bath). | the genes encoding the ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) from methylococcus capsulatus (bath) were localised to an 8.3-kb ecori fragment of the genome. genes encoding the large subunit ( cbbl), small subunit ( cbbs) and putative regulatory gene ( cbbq) were shown to be located on one cluster. surprisingly, cbbo, a second putative regulatory gene, was not located in the remaining 1.2-kb downstream (3') of cbbq. however, probing of the m. capsulatus (bath) genome with cbbo ... | 2002 | 11889481 |
| spectroscopic characterization of the no adduct of hydroxylamine oxidoreductase. | hydroxylamine oxidoreductase (hao) from the autotrophic nitrifying bacterium nitrosomonas europaea catalyzes the oxidation of nh2oh to no2-. the enzyme contains eight hemes per subunit which participate in catalysis and electron transport. no is found to bind to the enzyme and inhibit electron flow to the acceptor protein, cytochrome c554. no is found to oxidize either partially or fully reduced hao, but no will not reduce ferric hao. since no can be reduced but not oxidized to product by hao, n ... | 2002 | 11926822 |
| nitrite reductase of nitrosomonas europaea is not essential for production of gaseous nitrogen oxides and confers tolerance to nitrite. | a gene that encodes a periplasmic copper-type nitrite reductase (nirk) was identified in nitrosomonas europaea. disruption of this gene resulted in the disappearance of nir activity in cell extracts. the nitrite tolerance of nirk-deficient cells was lower than that of wild-type cells. unexpectedly, nirk-deficient cells still produced nitric oxide (no) and nitrous oxide (n(2)o), the latter in greater amounts than that of wild-type cells. this demonstrates that nirk is not essential for the produc ... | 2002 | 11948173 |
| solid-phase contact assay that uses a lux-marked nitrosomonas europaea reporter strain to estimate toxicity of bioavailable linear alkylbenzene sulfonate in soil. | information about in situ toxicity of the bioavailable pools of adsorptive soil pollutants is a prerequisite for proper ecological risk assessment in contaminated soils. such toxicity data may be obtained by assays allowing for direct exposure of introduced test microorganisms to the toxicants, as they appear in solid solution equilibria in the natural soil. we describe a novel sensitive solid-phase contact assay for in situ toxicity testing of soil pollutants based on a recombinant bioluminesce ... | 2002 | 12089034 |
| enumerating ammonia-oxidizing bacteria in environmental samples using competitive pcr. | primers targeting part of the ammonia-monooxygenase gene (amoa) have been used to detect and characterize ammonia-oxidizing bacteria (aob) in different environments. in this study, a quantitative polymerase chain reaction (pcr) technique using a competitive template for the amoa primer pair is described and evaluated. the method is based on addition of an internal standard to the pcr, a competitive template, which is amplified together with the template in the environmental sample. by adding dif ... | 2002 | 12133615 |
| exploration of inorganic c and n assimilation by soil microbes with time-of-flight secondary ion mass spectrometry. | stable c and n isotopes have long been used to examine properties of various c and n cycling processes in soils. unfortunately, relatively large sample sizes are needed for accurate gas phase isotope ratio mass spectrometric analysis. this limitation has prevented researchers from addressing c and n cycling issues on microbially meaningful scales. here we explored the use of time-of-flight secondary ion mass spectrometry (tof-sims) to detect 13c and 15n assimilation by individual bacterial cells ... | 2002 | 12147508 |
| detection of proteobacteria from the rumen by pcr using methanotroph-specific primers. | to detect proteobacteria, including methanotrophs, from the rumen fluid and the bacteria inhabiting the rumen epithelium. | 2002 | 12180951 |
| production of gaseous nitrogen compounds in a novel process for ammonium removal. | the production of gaseous nitrogen compounds, particularly the greenhouse gas nitrous oxide, was investigated in a novel process for ammonium removal from wastewater. the process is based on the adsorption of ammonium on zeolite followed by bioregeneration. the zeolite serves the dual purpose of an ion exchanger and a physical carrier for nitrifying bacteria which bio-regenerate the ammonium saturated mineral. an analysis of the nitrifying population composition in the reactor fed with simulated ... | 2002 | 12216627 |
| distribution and activity of ammonia oxidizing bacteria in a large full-scale trickling filter. | the biofilm in a full-scale nitrifying trickling filter (ntf) treating municipal wastewater has been investigated with microbiological methods using fluorescence in situ hybridization (fish) with 16s rrna oligonucleotide probes in combination with confocal laser scanning microscopy (clsm) and mathematical modeling using a dynamic multi-species biofilm reactor model. ammonia oxidizing bacteria (aob) were found to belong to the genus nitrosomonas at different depths in the ntf at every sampling oc ... | 2002 | 11996334 |
| melissa: a loop of interconnected bioreactors to develop life support in space. | the development of a loop of interconnected continuous bioreactors, aimed to provide life support in space, is reported. the complete loop concept consists of four bioreactors and one higher plant compartment. for its realization the continuous and controlled operation of the bioreactors is characterized, up to the pilot scale level, first for each individual reactor, second for the interconnected reactor operation. the results obtained with the two more advanced bioreactors in the micro ecologi ... | 2002 | 12385718 |
| anaerobic ammonia oxidation in the presence of nitrogen oxides (no(x)) by two different lithotrophs. | the anaerobic ammonia-oxidizing activity of the planctomycete candidatus "brocadia anammoxidans" was not inhibited by no concentrations up to 600 ppm and no2 concentrations up to 100 ppm. b. anammoxidans was able to convert (detoxify) no, which might explain the high no tolerance of this organism. in the presence of no2, the specific ammonia oxidation activity of b. anammoxidans increased, and nitrosomonas-like microorganisms recovered an no2-dependent anaerobic ammonia oxidation activity. addit ... | 2002 | 12406724 |
| effect of soil ammonium concentration on n2o release and on the community structure of ammonia oxidizers and denitrifiers. | the effect of ammonium addition (6.5, 58, and 395 microg of nh4+-n g [dry weight] of soil(-1)) on soil microbial communities was explored. for medium and high ammonium concentrations, increased n2o release rates and a shift toward a higher contribution of nitrification to n2o release occurred after incubation for 5 days at 4 degrees c. communities of ammonia oxidizers were assayed after 4 weeks of incubation by denaturant gradient gel electrophoresis (dgge) of the amoa gene coding for the small ... | 2002 | 12406765 |
| quantification of nitrosomonas oligotropha and nitrospira spp. using competitive polymerase chain reaction in bench-scale wastewater treatment reactors operating at different solids retention times. | the effect of solids retention time (srt) on ammonia-and nitrite-oxidizing bacteria was measured by nitrosomonas oligotropha-like ammonia monooxygenase a and nitrospira 16s rdna competitive polymerase chain reaction assays in a complete-mix, bench-scale, activated-sludge system. during steady-state operation, nitrification was complete in the 20- and 10-day srt reactors, nearly complete in the 5-day srt reactor, and incomplete in the 2-day srt reactor (76% ammonia oxidation and 85% nitrite oxida ... | 2002 | 12469950 |
| toxicity assessment of 255 chemicals to pure cultured nitrifying bacteria using biosensor. | the bioassay has been attracting attention as a method of toxicity assessments of micropollutants in the environment. in this study, we report the characteristics (selectivity and sensitivity) of the nitrifying bacteria biosensor for 255 kinds of chemicals as a model of chemical contaminant in the environment and the results of evaluation of mixed samples of several substances. in the nitrifying bacteria respiration inhibition test using the biosensor, 56 chemicals were detected. it was found th ... | 2002 | 12523774 |
| phylogeny and functional expression of ribulose 1,5-bisphosphate carboxylase/oxygenase from the autotrophic ammonia-oxidizing bacterium nitrosospira sp. isolate 40ki. | the autotrophic ammonia-oxidizing bacteria (aob), which play an important role in the global nitrogen cycle, assimilate co(2) by using ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco). here we describe the first detailed study of rubisco (cbb) genes and proteins from the aob. the cbbls genes from nitrosospira sp. isolate 40ki were cloned and sequenced. partial sequences of the rubisco large subunit (cbbl) from 13 other aob belonging to the beta and gamma subgroups of the class proteobac ... | 2002 | 11751824 |
| application of toxicity monitor using nitrifying bacteria biosensor to sewerage systems. | toxic substances may be included in wastewater influent and can damage biological processing of wastewater treatment, therefore continuous toxic-monitoring of wastewater influent is needed. this paper describes the potential toxic-monitoring applications of the toxicity monitor using a nitrifying bacteria biosensor to sewerage systems. the results of sensitivity tests show that aspects of wastewater do not affect the sensor sensitivity and confirm that the sensor can be applied to wastewater mon ... | 2002 | 11936643 |
| specific layers in aerobically grown microbial granules. | to determine the optimal size of aerobically grown granules for wastewater treatment by measuring specific layers within the granules. | 2002 | 11940154 |
| single-base-pair discrimination of terminal mismatches by using oligonucleotide microarrays and neural network analyses. | the effects of single-base-pair near-terminal and terminal mismatches on the dissociation temperature (t(d)) and signal intensity of short dna duplexes were determined by using oligonucleotide microarrays and neural network (nn) analyses. two perfect-match probes and 29 probes having a single-base-pair mismatch at positions 1 to 5 from the 5' terminus of the probe were designed to target one of two short sequences representing 16s rrna. nonequilibrium dissociation rates (i.e., melting profiles) ... | 2002 | 11772632 |
| quantification of nitrosomonas oligotropha-like ammonia-oxidizing bacteria and nitrospira spp. from full-scale wastewater treatment plants by competitive pcr. | utilizing the principle of competitive pcr, we developed two assays to enumerate nitrosomonas oligotropha-like ammonia-oxidizing bacteria and nitrite-oxidizing bacteria belonging to the genus nitrospira: the specificities of two primer sets, which were designed for two target regions, the amoa gene and nitrospira 16s ribosomal dna (rdna), were verified by dna sequencing. both assays were optimized and applied to full-scale, activated sludge wastewater treatment plant (wwtp) samples. if it was as ... | 2002 | 11772633 |
| diversity of ammonia monooxygenase operon in autotrophic ammonia-oxidizing bacteria. | autotrophic ammonia-oxidizing bacteria use the essential enzyme ammonia monooxygenase (amo) to transform ammonia to hydroxylamine. the amo operon consists of at least three genes, amoc, amoa, and amob; amoa encodes the subunit containing the putative enzyme active site. the use of the amo genes as functional markers for ammonia-oxidizing bacteria in environmental applications requires knowledge of the diversity of the amo operon on several levels: (1) the copy number of the operon in the genome, ... | 2002 | 11807563 |
| nitrification in the schelde estuary: methodological aspects and factors influencing its activity. | abstract we present a 15-month dataset on nitrification measurements in the schelde estuary (belgium and the netherlands). nitrification was estimated using the n-serve sensitive dark (14)c-bicarbonate incorporation technique. a peak of nitrification activity was observed in the freshwater part of the estuary. downstream from this peak, nitrification declined, probably because of ammonium limitation. a range of nitrification inhibitors was tested on both a nitrosomonas europaea culture and estua ... | 2002 | 19709269 |
| molecular characterization of microbial community in nitrate-removing activated sludge. | abstract the microbial community composition and dominant denitrifying populations in high-nitrate-removing (cr-i) and low-nitrate-removing (cr-ii) activated sludge from continuous bioreactors were investigated with most probable number (mpn) enumeration, fluorescence in situ hybridization (fish) and 16s rdna characterization. mpns of nitrate-reducing bacteria of sludge cr-i and sludge cr-ii were 2.82x10(7) and 2.69x10(4) colony-forming units ml(-1), respectively. eight denitrifying bacteria and ... | 2002 | 19709242 |
| application of temperature gradient gel electrophoresis to the characterization of a nitrifying bioaugmentation product. | the microbial population of a nitrifying bioaugmentation product (nbp) has been examined using a combination of conventional bacteriological methods and modern molecular techniques. variable region 3 (v3) of the 16s rrna genes of the bacteria in nbp was amplified via the polymerase chain reaction (pcr) with universal eubacterial primers and analyzed via temperature gradient gel electrophoresis (tgge). two of the predominant pcr products in nbp were purified from the tgge gel matrix, reamplified ... | 2003 | 19719689 |
| composition and diversity of ammonia-oxidising bacterial communities in wastewater treatment reactors of different design treating identical wastewater. | autotrophic ammonia-oxidising bacteria (aob) are a crucial component of the microbial communities of nitrifying wastewater treatment systems. nitrification is known to occur in reactors of different configuration, but whether aob communities are different in reactors of different design is unknown. we compared the diversity and community structure of the betaproteobacterial aob in two full-scale treatment reactors - a biological aerated filter (baf) and a trickling filter - receiving the same wa ... | 2003 | 19719680 |
| nitrifying microbial community analysis of nitrite accumulating biofilm reactor by fluorescence in situ hybridization. | biological nitrogen removal via nitrite pathway in wastewater treatment is very important especially in the cost of aeration and as an electron donor for denitrification. wastewater nitrification and nitrite accumulations were carried out in a biofllm reactor. the biofilm reactor showed almost complete nitrification and most of the oxidized ammonium was present as nitrite at the ammonium load of 1.2 kg n/m3/d. nitrite accumulation was achieved by the selective inhibition of nitrite oxidizers by ... | 2003 | 12578180 |
| microbial composition and structure of a rotating biological contactor biofilm treating ammonium-rich wastewater without organic carbon. | high nitrogen losses were observed in a rotating biological contactor (rbc) treating ammonium-rich (up to 500 mg nh4(+)-n/l) but organic-carbon-poor leachate from a hazardous waste landfill in kölliken, switzerland. the composition and spatial structure of the microbial community in the biofilm on the rbc was analyzed with specific attention for the presence of aerobic ammonium and nitrite oxidizing bacteria and anaerobic ammonium oxidizers. anaerobic ammonium oxidation (anammox) involves the ox ... | 2003 | 12704553 |
| use of multidimensional scaling in the selection of wastewater toxicity test battery components. | in aquatic toxicity testing, no single test species is sensitive to all toxicants. therefore, test batteries consisting of several individual assays are becoming more common. the organisms in a test battery should be representative of the entire system of interest. the results of the assays should be complementary to other components in the test battery to avoid redundancy. with the aid of multidimensional scaling (mds), a multivariate statistical method, we examined the toxicity data of five bi ... | 2003 | 12600394 |
| diversity of nitrifying bacteria in full-scale chloraminated distribution systems. | chloramination for secondary disinfection of drinking water often promotes the growth of nitrifying bacteria in the distribution system due to the ammonia introduced by chloramine formation and decay. this study involved the application of molecular biology techniques to explore the types of ammonia-oxidizing bacteria (aob) and nitrite-oxidizing bacteria (nob) present in several full-scale chloraminated systems. the results of aob community characterization indicated the ubiquitous detection of ... | 2003 | 12465801 |
| real-time pcr quantification of nitrifying bacteria in a municipal wastewater treatment plant. | real-time pcr assays using taqman or molecular beacon probes were developed and optimized for the quantification of total bacteria, the nitrite-oxidizing bacteria nitrospira, and nitrosomonas oligotropha-like ammonia oxidizing bacteria (aob) in mixed liquor suspended solids (mlss) from a municipal wastewater treatment plant (wwtp) using a single-sludge nitrification process. the targets for the real-time pcr assays were the 16s rrna genes (16s rdna) for bacteria and nitrospira spp. and the amoa ... | 2003 | 12564907 |
| nitrogen isotopomer site preference of n2o produced by nitrosomonas europaea and methylococcus capsulatus bath. | the relative importance of individual microbial pathways in nitrous oxide (n(2)o) production is not well known. the intramolecular distribution of (15)n in n(2)o provides a basis for distinguishing biological pathways. concentrated cell suspensions of methylococcus capsulatus bath and nitrosomonas europaea were used to investigate the site preference of n(2)o by microbial processes during nitrification. the average site preference of n(2)o formed during hydroxylamine oxidation by m. capsulatus b ... | 2003 | 12661029 |
| community structure of ammonia-oxidizing bacteria within anoxic marine sediments. | the potential for oxidation of ammonia in anoxic marine sediments exists through anaerobic oxidation by nitrosomonas-like organisms, utilizing nitrogen dioxide, coupling of nitrification, manganese reduction, and anaerobic oxidation of ammonium by planctomycetes (the anammox process). here we describe the presence of microbial communities with the potential to carry out these processes in a natural marine sediment system (loch duich, scotland). natural microbial communities of planctomycetales-v ... | 2003 | 12620817 |
| excision and integration of cassettes by an integron integrase of nitrosomonas europaea. | we found in the environmental strain nitrosomonas europaea a chromosomal integron-like structure with an integrase gene, inti(neu). we have tested the capacity of the intineu integrase to excise and integrate several resistance gene cassettes. the results allow us to consider intineu a new functional integron integrase. | 2003 | 12618471 |
| characterization of microbial communities and composition in constructed dairy wetland wastewater effluent. | constructed wetlands have been recognized as a removal treatment option for high concentrations of contaminants in agricultural waste before land application. the goal of this study was to characterize microbial composition in two constructed wetlands designed to remove contaminants from dairy washwater. water samples were collected weekly for 11 months from two wetlands to determine the efficiency of the treatment system in removal of chemical contaminants and total and fecal coliforms. the red ... | 2003 | 12957887 |
| biological treatment process of air loaded with an ammonia and hydrogen sulfide mixture. | the physico-chemical characteristics of granulated sludge lead us to develop its use as a packing material in air biofiltration. then, the aim of this study is to investigate the potential of unit systems packed with this support in terms of ammonia and hydrogen sulfide emissions treatment. two laboratory scale pilot biofilters were used. a volumetric load of 680 g h2s m(-3) empty bed day(-1) and 85 g nh3 m(-3) empty bed day(-1) was applied for eight weeks to a unit called bgsn (column packed wi ... | 2003 | 12656240 |
| lessons from the genome of a lithoautotroph: making biomass from almost nothing. | 2003 | 12700247 | |
| nitrification efficiency and nitrifying bacteria abundance in combined as-rbc and a2o systems. | this study makes a comparison between the nitrification performance of tncu-i (a combined activated sludge-rotating biological contactor process) and a2o systems by the use of a pilot plant and batch experiments. the nitrifier abundance in both systems was determined, using cloning-denaturing gradient gel electrophoresis (dgge) and fluorescent in-situ hybridization (fish), to investigate the role of rotating biological contactor in the tncu-i process. the stability of the nitrification performan ... | 2003 | 12727236 |
| optimization of single-base-pair mismatch discrimination in oligonucleotide microarrays. | the discrimination between perfect-match and single-base-pair-mismatched nucleic acid duplexes was investigated by using oligonucleotide dna microarrays and nonequilibrium dissociation rates (melting profiles). dna and rna versions of two synthetic targets corresponding to the 16s rrna sequences of staphylococcus epidermidis (38 nucleotides) and nitrosomonas eutropha (39 nucleotides) were hybridized to perfect-match probes (18-mer and 19-mer) and to a set of probes having all possible single-bas ... | 2003 | 12732557 |
| canon and anammox in a gas-lift reactor. | anoxic ammonium oxidation (anammox) and completely autotrophic nitrogen removal over nitrite (canon) are new and promising microbial processes to remove ammonia from wastewaters characterized by a low content of organic materials. these two processes were investigated on their feasibility and performance in a gas-lift reactor. the anammox as well as the canon process could be maintained easily in a gas-lift reactor, and very high n-conversion rates were achieved. an n-removal rate of 8.9 kg n (m ... | 2003 | 12586414 |
| wide distribution of a novel pmoa-like gene copy among type ii methanotrophs, and its expression in methylocystis strain sc2. | experiments were conducted to determine if a novel pmoa-like gene (pmoa2) recently discovered in the methane-oxidizing bacterium methylocystis strain sc2 (p. f. dunfield, m. tchawa yimga, s. d. dedysh, u. berger, w. liesack, and j. heyer, fems microbiol. ecol. 41:17-26, 2002) is present in other methane-oxidizing bacteria (mob), and if it is expressed. a newly developed primer combination (pmoa206f-pmoa703b) allowed a differential detection of pmoa1 and pmoa2. by using this primer combination, w ... | 2003 | 12957949 |
| characterization of an autotrophic nitrogen-removing biofilm from a highly loaded lab-scale rotating biological contactor. | in this study, a lab-scale rotating biological contactor (rbc) treating a synthetic nh(4)(+) wastewater devoid of organic carbon and showing high n losses was examined for several important physiological and microbial characteristics. the rbc biofilm removed 89% +/- 5% of the influent n at the highest surface load of approximately 8.3 g of n m(-2) day(-1), with n(2) as the main end product. in batch tests, the rbc biomass showed good aerobic and anoxic ammonium oxidation (147.8 +/- 7.6 and 76.5 ... | 2003 | 12788771 |
| complete genome sequence of the ammonia-oxidizing bacterium and obligate chemolithoautotroph nitrosomonas europaea. | nitrosomonas europaea (atcc 19718) is a gram-negative obligate chemolithoautotroph that can derive all its energy and reductant for growth from the oxidation of ammonia to nitrite. nitrosomonas europaea participates in the biogeochemical n cycle in the process of nitrification. its genome consists of a single circular chromosome of 2,812,094 bp. the gc skew analysis indicates that the genome is divided into two unequal replichores. genes are distributed evenly around the genome, with approximate ... | 2003 | 12700255 |
| linking nitrifying biofilm structure and function through fluorescent in situ hybridization and evaluation of nitrification capacity. | fluorescent in situ hybridization (fish) was used to quantify the ammonia-oxidizing populations within intact biofilm samples collected from a full-scale nitrifying trickling filter (ntf). ammonia, nitrite, and nitrate concentrations were measured for aqueous samples taken in conjunction with biofilm samples at multiple filter depths. the ammonia removal capability of collected biofilms was evaluated by transferring the biofilms to laboratory batch reactors. nitrate plus nitrite generation rates ... | 2003 | 12837026 |
| susceptibility of ammonia-oxidizing bacteria to nitrification inhibitors. | activity of nitrification inhibitors to several typical ammonia-oxidizing bacteria isolated recently, i. e. nitrosococcus, nitrosolobus, nitrosomonas, nitrosospira and nitrosovibrio species was assayed using 2-amino-4-methyl-trichloromethyl-1,3,5-triazine (mast), 2-amino-4-tribromomethyl-6-trichloromethyl-1,3,5-triazine (br-mast), 2-chloro-6-trichloromethylpyridine (nitrapyrin) and others, and compared to confirm the adequate control of ammonia-oxidizing bacteria by the inhibitors. the order of ... | 2003 | 12710742 |
| molecular biological methods (dgge) as a tool to investigate nitrification inhibition in wastewater treatment. | incomplete nitrification at an activated sludge plant for biological pre-treatment of rendering plant effluents led to a detailed investigation on the origin and solution of this problem. preliminary studies revealed that an inhibition of ammonia oxidising microorganisms (aom) by process waters of the rendering plant was responsible for the situation. we were able to show a correlation between the existence of specific aom and nitrification capacity expressed as oxygen uptake rate for maximal ni ... | 2003 | 12906286 |
| 16s rrna and amoa-based phylogeny of 12 novel betaproteobacterial ammonia-oxidizing isolates: extension of the dataset and proposal of a new lineage within the nitrosomonads. | the phylogenetic relationship of 12 ammonia-oxidizing isolates (eight nitrosospiras and four nitrosomonads), for which no gene sequence information was available previously, was investigated based on their genes encoding 16s rrna and the active site subunit of ammonia monooxygenase (amoa). almost full-length 16s rrna gene sequences were determined for the 12 isolates. in addition, 16s rrna gene sequences of 15 ammonia-oxidizing bacteria (aob) published previously were completed to allow for a mo ... | 2003 | 13130037 |
| community analysis of ammonia and nitrite oxidizers during start-up of nitritation reactors. | partial nitrification of ammonium to nitrite under oxic conditions (nitritation) is a critical process for the effective use of alternative nitrogen removal technologies from wastewater. here we investigated the conditions which promote establishment of a suitable microbial community for performing nitritation when starting from regular sewage sludge. reactors were operated in duplicate under different conditions (ph, temperature, and dilution rate) and were fed with 50 mm ammonium either as syn ... | 2003 | 12788718 |
| spectroscopic characterization and assignment of reduction potentials in the tetraheme cytochrome c554 from nitrosomonas europaea. | the tetraheme cytochrome c(554) (cyt c(554)) from nitrosomonas europaea is an essential electron transfer component in the biological oxidation of ammonia. the protein contains one 5-coordinate heme and three bis-his coordinated hemes in a 3d arrangement common to a newly characterized class of multiheme proteins. the ligand binding, electrochemical properties, and heme-heme interactions are investigated with mössbauer and x- and q-band (parallel/perpendicular mode) epr spectroscopy. the results ... | 2003 | 12580599 |
| structure and activity of multiple nitrifying bacterial populations co-existing in a biofilm. | a biofilm from a nitrifying pilot-scale sequencing batch reactor was investigated for effects of varying process conditions on its microscale activity and structure. microsensor measurements of oxygen, substrates and products of nitrification were applied under incubation at different ammonium and oxygen concentrations which reflected various situations during a treatment cycle. a high net n loss was observed under high ammonium (ha) concentrations in contrast to low ones. additionally, results ... | 2003 | 12713462 |
| activity and population dynamics of heterotrophic and ammonia-oxidizing microorganisms in soil surrounding sludge bands spiked with linear alkylbenzene sulfonate: a field study. | recent research has documented soil microorganisms to be rather sensitive to linear alkylbenzene sulfonates (las), which may enter the soil environment in considerable quantities following sewage sludge disposal. we here report field effects of las on selected microbial populations present in a sandy soil surrounding well-defined sludge bands spiked with high but realistic las levels (7.1 or 31.3 g/kg). surprisingly, las had no effect on heterotrophic respiration in the sludge compartment per se ... | 2003 | 12685718 |
| cytochrome p460 of nitrosomonas europaea. formation of the heme-lysine cross-link in a heterologous host and mutagenic conversion to a non-cross-linked cytochrome c'. | the heme of cytochrome p460 of nitrosomonas europaea, which is covalently crosslinked to two cysteines of the polypeptide as with all c-type cytochromes, has an additional novel covalent crosslink to lysine 70 of the polypeptide [arciero, d.m. & hooper, a.b. (1997) febs lett.410, 457-460]. the protein can catalyze the oxidation of hydroxylamine. the gene for this protein, cyp, was expressed in pseudomonas aeruginosa strain pao laci, resulting in formation of a holo-cytochrome p460 which closely ... | 2003 | 12709052 |
| selective one-electron reduction of nitrosomonas europaea hydroxylamine oxidoreductase with nitric oxide. | hydroxylamine oxidoreductase (hao) from the autotrophic bacterium nitrosomonas europaea catalyzes the 4-e- oxidation of nh2-oh to no2-. the e- are transferred from nh2oh to an unusual 5-coordinate heme known as p460, which is the active site of hao, and from there to an array of seven c-type hemes. no., generated by laser flash photolysis of n,n'-bis(carboxymethyl)-n,n'-dinitroso-1,4-phenylenediamine, is found to act as a 1-e- donor to hao. most likely no. binds p460 to yield a [fe(no)]6 moiety, ... | 2003 | 12693206 |
| [study on the ammonia-oxidizing bacteria from activated sludge samples by the molecular analysis]. | the molecular analysis methods of pcr amplification, random cloning and sequencing were used to investigate the ammonia-oxidizing bacterial community composition and the activity of ammonia-monooxygenase (amo) from the activated sludge samples of an industrial wastewater treatment plant receiving sewage with high ammonia concentration. it is the first time to use pcr-dgge combined technique to analysis the difference of dominant bacterial community compositions of the activated sludge samples in ... | 2003 | 16279205 |
| [preliminary study of characteristics of a special nitrosomonas]. | a special obligately-autotrophic nitrosomonas was isolated from high temperature and hypersaline drainage water obtained off a wastewater treatment plant. it was gram-negative, nonsporulating, ellipsoidal or short-rod shaped bacterium that singly arranged or arranged in a circle or in a row. cells were 0.7 to 0.9 microm wide and 1.2 to 1.98 microm long. electron-microscopic scanning of these cells indicated that they were wrapped by unknown fluff-like matter. they oxidized ammonium to nitrite an ... | 2003 | 16276877 |
| molecular analysis of microbial communities in nitrification and denitrification reactors treating high ammonia leachate. | molecular analysis of microbial populations in two bench-scale nitrification and denitrification reactors fed with high ammonia landfill leachate was conducted in this study by using dgge, cloning, and fish techniques in addition to classical efficiency control parameters. nitrification tank was operated with a computer-controlled alkalinity dosing system to supply the alkalinity intermittently as consumed on the basis of on-line ph monitoring. by keeping the ph at 7.0 with this system, 99% nitr ... | 2003 | 14524656 |
| characterization of nitrifying granules produced in an aerobic upflow fluidized bed reactor. | since nitrification is the rate-determining step in the biological nitrogen removal from wastewater, many research studies have been conducted on the immobilization of nitrifying bacteria. in this research, granulation of nitrifying bacteria in an aerobic upflow fluidized bed (aufb) reactor in a nitrification process for inorganic wastewater containing 500 g/m(3) of nh(4)(+)-n was investigated. it was observed that spherical, pseudocubic and elliptical granules with a diameter of 346 microm were ... | 2003 | 14604643 |
| the isotope array, a new tool that employs substrate-mediated labeling of rrna for determination of microbial community structure and function. | a new microarray method, the isotope array approach, for identifying microorganisms which consume a (14)c-labeled substrate within complex microbial communities was developed. experiments were performed with a small microarray consisting of oligonucleotide probes targeting the 16s rrna of ammonia-oxidizing bacteria (aob). total rna was extracted from a pure culture of nitrosomonas eutropha grown in the presence of [(14)c]bicarbonate. after fluorescence labeling of the rna and microarray hybridiz ... | 2003 | 14602652 |
| chemolithoorganotrophic growth of nitrosomonas europaea on fructose. | the nitrifying bacterium nitrosomonas europaea can obtain all its carbon for growth from co(2) and all its energy and reductant for growth from the oxidation of nh(3) and is considered an obligate chemolithoautotroph. previous studies have shown that n. europaea can utilize limited amounts of certain organic compounds, including amino acids, pyruvate, and acetate, although no organic compound has been reported to support the growth of n. europaea. the recently completed genomic sequence of n. eu ... | 2003 | 14617645 |
| nitrification and nitrifying bacteria in the lower seine river and estuary (france). | the achères wastewater treatment plant, located just downstream of paris, discharges its effluents into the lower seine river. the effluents contain large numbers of heterotrophic bacteria, organic matter, and ammonium and are a source of nitrifying bacteria. as a result, degradation of organic matter by heterotrophic bacteria and subsequent oxygen depletion occur immediately downstream of the effluent outlet, whereas nitrifying bacteria apparently need to build up a significant biomass before a ... | 2003 | 14660353 |
| metabolism of inorganic n compounds by ammonia-oxidizing bacteria. | ammonia oxidizing bacteria extract energy for growth from the oxidation of ammonia to nitrite. ammonia monooxygenase, which initiates ammonia oxidation, remains enigmatic given the lack of purified preparations. genetic and biochemical studies support a model for the enzyme consisting of three subunits and metal centers of copper and iron. knowledge of hydroxylamine oxidoreductase, which oxidizes hydroxylamine formed by ammonia monooxygenase to nitrite, is informed by a crystal structure and det ... | 2003 | 14695127 |
| dynamic response of nitrifying activated sludge batch culture to increased chloride concentration. | dynamic response of nitrifying activated sludge batch cultures to increased chloride concentration was studied in this paper, which focused upon the changes in the specific nitrification rate (snr) and nitrifier population when the chloride level was gradually or stepwise increased to 30,000 mg cl l-1. the dominant species of ammonia-oxidizers and nitriteoxidizers in the population were examined by fluorescent in situ hybridization technique with 16s rrna-targeted oligonucleotide probes. it was ... | 2003 | 14509699 |
| a comparitive study of ammonia-oxidizing bacteria in lab-scale industrial wastewater treatment reactors. | the diversity and community structure of the beta-proteobacterial ammonia oxidising bacteria (aob) in a range of different lab-scale industrial wastewater treatment reactors were compared. three of the reactors treat waste from mixed domestic and industrial sources whereas the other reactor treats waste solely of industrial origin. pcr with aob selective primers was combined with denaturing gradient ge electrophoresis to allow comparative analysis of the dominant aob populations and the phylogen ... | 2003 | 14518850 |
| analysis of size distribution and areal cell density of ammonia-oxidizing bacterial microcolonies in relation to substrate microprofiles in biofilms. | a fine-scale in situ spatial organization of ammonia-oxidizing bacteria (aob) in biofilms was investigated by combining molecular techniques (i.e., fluorescence in situ hybridization (fish) and 16s rdna-cloning analysis) and microelectrode measurements. important parameters of aob microcolonies such as size distribution and areal cell density of the microcolonies were determined and correlated with substrate microprofiles in the biofilms. in situ hybridization with a nested 16s rrna-targeted oli ... | 2004 | 14705015 |
| comparative analysis of genetic diversity and expression of amoa in wastewater treatment processes. | the genetic diversity and expression of amoa of autotrophic ammonia oxidizers in wastewater treatment processes were investigated by rt-pcr and denaturing gradient gel electrophoresis (dgge) in order to identify active components of ammonia-oxidizer populations in a such processes. ammonia oxidizers, evidenced by the presence of amoa mrna, were regarded as metabolically active. the dgge profiles derived from amoa mrna and from its gene, which were amplified by rt-pcr or pcr using samples collect ... | 2004 | 14758520 |
| inhibition of membrane-bound methane monooxygenase and ammonia monooxygenase by diphenyliodonium: implications for electron transfer. | diphenyliodonium (dpi) is known to irreversibly inactivate flavoproteins. we have found that dpi inhibits both membrane-bound methane monooxygenase (pmmo) from methylococcus capsulatus and ammonia monooxygenase (amo) of nitrosomonas europaea. the effect of dpi on nadh-dependent pmmo activity in vitro is ascribed to inactivation of ndh-2, a flavoprotein which we proposed catalyzes reduction of the quinone pool by nadh. dpi is a potent inhibitor of type 2 nadh:quinone oxidoreductase (ndh-2), with ... | 2004 | 14761987 |
| a distinctive electrocatalytic response from the cytochrome c peroxidase of nitrosomonas europaea. | here the cytochrome c peroxidase (ccp) from nitrosomonas europaea is examined using the technique of catalytic protein film voltammetry. submonolayers of the bacterial diheme enzyme at a pyrolytic graphite edge electrode give catalytic, reductive signals in the presence of the substrate hydrogen peroxide. the resulting waveshapes indicate that ccp is bound non-covalently in a highly active configuration. the native enzyme has been shown to possess two heme groups of low and high potential (l and ... | 2004 | 14973133 |
| influence of soil moisture on linear alkylbenzene sulfonate-induced toxicity in ammonia-oxidizing bacteria. | moisture affects bioavailability and fate of pollutants in soil, but very little is known about moisture-induced effects on pollutant toxicity. we here report on a modifying effect of moisture on degradation of linear alkylbenzene sulfonates (lass) and on their toxicity towards ammonia-oxidizing bacteria (aob) in agricultural soil. in soil spiked with two las levels (250 or 1,000 mg/kg) and incubated at four different moisture levels (9-100% of water-holding capacity), degradation was strongly a ... | 2004 | 14982383 |
| genera-specific immunofluorescence labeling of ammonia oxidizers with polyclonal antibodies recognizing both subunits of the ammonia monooxygenase. | polyclonal antibodies that recognize the two subunits amoa and amob of the ammonia monooxygenase (amo) were applied to identify ammonia-oxidizing bacteria by immunofluorescence (if) labeling in pure, mixed, and enriched cultures. the antibodies against the amoa were produced using a synthetic peptide of the amoa of nitrosomonas eutropha, whereas the antibodies against the amob had been developed previously is against the whole b-subunit of the amo [pinck et al. (2001) appl environ microbiol 67:1 ... | 2004 | 14994172 |
| start-up of autotrophic nitrogen removal reactors via sequential biocatalyst addition. | a procedure for start-up of oxygen-limited autotrophic nitrification-denitrification (oland) in a lab-scale rotating biological contactor (rbc) is presented. in this one-step process, nh4+ is directly converted to n2 without the need for an organic carbon source. the approach is based on a sequential addition of two types of easily available biocatalyst to the reactor during start-up: aerobic nitrifying and anaerobic, granular methanogenic sludge. the first is added as a source of aerobic ammoni ... | 2004 | 14998042 |
| use of amob as a new molecular marker for ammonia-oxidizing bacteria. | specific molecular determination and classification of ammonia-oxidizing bacteria have relied on the use of conventional markers such as 16s rdna. however, this gene does not satisfactorily provide a wide vision of all phylogenetic lineages. despite the initial expectations, the use of functional genes as for example amoa has only been useful to corroborate the established taxonomy. ammonia-oxidizing bacteria constitute a physiological group that crosses over principal phylogenetic radiations. t ... | 2004 | 15003690 |
| physiologic and proteomic evidence for a role of nitric oxide in biofilm formation by nitrosomonas europaea and other ammonia oxidizers. | no, a free radical gas, is the signal for nitrosomonas europaea cells to switch between different growth modes. at an no concentration of more than 30 ppm, biofilm formation by n. europaea was induced. no concentrations below 5 ppm led to a reversal of the biofilm formation, and the numbers of motile and planktonic (motile-planktonic) cells increased. in a proteomics approach, the proteins expressed by n. europaea were identified. comparison studies of the protein patterns of motile-planktonic a ... | 2004 | 15090520 |
| ammonium and hydroxylamine uptake and accumulation in nitrosomonas. | starved cells of nitrosomonas europaea and further ammonia oxidizers were able to rapidly accumulate ammonium and hydroxylamine to an internal concentration of about 1 and 0.8 m, respectively. in kinetic studies, the uptake/accumulation rates for ammonium [3.1 mmol (g protein)(-1) min(-1)] and hydroxylamine [4.39 mmol (g protein)(-1) min(-1)] were determined. the uptake and accumulation process of ammonium and hydroxylamine was not coupled to ammonia or hydroxylamine oxidation and nitrite was no ... | 2004 | 15133102 |
| community analysis of ammonia oxidizer in the oxygen-limited nitritation stage of oland system by dgge of pcr amplified 16s rdna fragments and fish. | oland (oxygen limited autotrophic nitrification and denitrification) nitrogen removal system was constructed by coupling with oxygen limited nitritation stage and anaerobic ammonium oxidation stage. ammonia oxidizer, as a kind of key bacteria in n cycle, plays an important role at the oxygen limited nitritation stage of oland nitrogen removal system. in this study, specific amplification of 16s rdna fragment of ammonia oxidizer by nested pcr, separation of mixed pcr samples by denaturing gradien ... | 2004 | 15559824 |
| fluorescence in situ hybridization analysis of nitrifiers in piggery wastewater treatment reactors. | fluorescence in situ hybridization (fish) was performed to analyze the nitrifying microbial communities in an activated sludge reactor (asr) and a fixed biofilm reactor (fbr) for piggery wastewater treatment. heterotrophic oxidation and nitrification were occurring simultaneously in the asr and the cod and nitrification efficiencies depend on the loads. in the fbr nitrification efficiency also depends on ammonium load to the reactor and nitrite was accumulated when free ammonia concentration was ... | 2004 | 15137442 |
| effects of seawater salinity on nitrite accumulation in short-range nitrification to nitrite as end product. | the effect of seawater salinity on nitrite accumulation in short-range nitrification to nitrite as the end product was studied by using a sbr. experimental results indicated that the growth of nitrobacteria was inhibited and very high levels of nitrite accumulation at different salinities were achieved under the conditions of 25-28 degrees c, ph 7.5-8.0, and the influent ammonia nitrogen of 40-70 mg/l when seawater flow used to flush toilet was less than 35% (salinity 12393 mg/l, cl- 6778 mg/l) ... | 2004 | 15137648 |
| biodegradation of natural and synthetic estrogens by nitrifying activated sludge and ammonia-oxidizing bacterium nitrosomonas europaea. | this report describes the uses of nitrifying activated sludge (nas) and ammonia-oxidizing bacterium nitrosomonas europaea to significantly degrade estrone (e1), 17beta-estradiol (e2), estriol (e3), and 17alpha-ethynylestradiol (ee2). using nas, the degradation of estrogens obeyed first-order reaction kinetics with degradation rate constants of 0.056 h(-1) for e1, 1.3 h(-1) for e2, 0.030 h(-1) for e3, and 0.035 h(-1) for ee2, indicating that e2 was most easily degraded. then, we confirmed that e2 ... | 2004 | 15142793 |
| the transcription of the cbb operon in nitrosomonas europaea. | nitrosomonas europaea is an aerobic ammonia-oxidizing bacterium that participates in the c and n cycles. n. europaea utilizes co(2) as its predominant carbon source, and is an obligate chemolithotroph, deriving all the reductant required for energy and biosynthesis from the oxidation of ammonia (nh(3)) to nitrite (). this bacterium fixes carbon via the calvin-benson-bassham (cbb) cycle via a type i ribulose bisphosphate carboxylase/oxygenase (rubisco). the rubisco operon is composed of five gene ... | 2004 | 15184573 |
| nitrosomonas europaea expresses a nitric oxide reductase during nitrification. | in this paper, we report the identification of a norcbqd gene cluster that encodes a functional nitric oxide reductase (nor) in nitrosomonas europaea. disruption of the norb gene resulted in a strongly diminished nitric oxide (no) consumption by cells and membrane protein fractions, which was restored by the introduction of an intact norcbqd gene cluster in trans. norb-deficient cells produced amounts of nitrous oxide (n2o) equal to that of wild-type cells. norcb-dependent activity was present d ... | 2004 | 15205449 |
| evaluating the effect of dissolved oxygen on ammonia-oxidizing bacterial communities in activated sludge. | the effect of dissolved oxygen (do) on the communities of ammonia-oxidizing bacteria (aob) in activated sludge was evaluated in lab-scale and full-scale reactors using the amoa gene as the basis for phylogenetic comparisons. under controlled laboratory conditions, two chemostats seeded with activated sludge from the same source were operated with high-do (8.5 mg/l) and low-do (0.24 and 0.12 mg/l) concentrations for a period of 300 days. at the end of the operation period, the chemostats had enri ... | 2004 | 15276744 |
| effects of hydroxylamine on microbial community structure and function of autotrophic nitrifying biofilms determined by in situ hybridization and the use of microelectrodes. | effects of hydroxylamine (nh2oh), an intermediate of nh4+ oxidation, on microbial community structure and function of two autotrophic nitrifying biofilms fed with and without nh2oh were analyzed by a 16s rrna approach and the use of microelectrodes. in the nh2oh-added biofilm, partial oxidation of nh4+ to no2- was observed, whereas complete oxidation of nh4+ to no3- was achieved in the control biofilm. in situ hybridization results revealed that no nitrite-oxidizing bacteria (nob) hybridized wit ... | 2004 | 15303724 |
| high nitrification rate at low ph in a fluidized bed reactor with chalk as the biofilm carrier. | a typical steady state bulk ph of about 5 was established in a nitrifying fluidized bed with chalk as the only buffer agent. in spite of the low ph, high rate nitrification was observed with the nitrification kinetic parameters in the chalk reactor similar to those of biological reactors operating at ph>7. various methods were used to determine the reasons for high rate nitrification at such low ph including (i) determination of bacterial species, (ii) microsensor measurements in the biofilm, an ... | 2004 | 15303729 |
| effect of solid hold-up on nitrite accumulation in a biofilm reactor--molecular characterization of nitrifying communities. | biological ammonium oxidation was carried out in two inverse turbulent bed reactors fed with synthetic mineral wastewater containing a high ammonium concentration (100 mg n-nh4+/l). both reactors were started-up and operated in the same conditions except for the solid carrier concentration: the solid hold-up ratios applied, defined as the ratios of static to expanded bed height, were 0.1 and 0.3 in reactors r10 and r30 respectively. these two solid hold-up ratios generate different particle-to-p ... | 2004 | 15303732 |
| a two-stage sbr process for removal of organic substrate and nitrogen via nitrite-type nitrification-denitrification. | a two-stage sbr process (tssbr) was applied for the treatment of wastewater with high strength cod and nitrogen. most of organic substrate was removed in the first stage sbr reactor (sbr1) under the aerobic condition. subsequently the second stage sbr reactor (sbr2) firstly was operated under the aerobic condition for simultaneous nitrite-type nitrification and removal of a small amount of residual organic substrate. nitrification was controlled to the nitrite-type nitrification. then denitrific ... | 2004 | 15332681 |
| characterization of a small metal binding protein from nitrosomonas europaea. | a small metal-binding protein (smbp) with no known similarity to other proteins in current databases was isolated and characterized from the periplasm of nitrosomonas europaea. the primary structure of this small (9.9 kda) monomeric protein is characterized by a series of 10 repeats of a seven amino acid motif and an unusually high number of histidine residues. the protein was isolated from n. europaea with cu(ii) bound but was found to be capable of binding multiple equivalents of a variety of ... | 2004 | 15366930 |
| a challenge for 21st century molecular biology and biochemistry: what are the causes of obligate autotrophy and methanotrophy? | we assess the use to which bioinformatics in the form of bacterial genome sequences, functional gene probes and the protein sequence databases can be applied to hypotheses about obligate autotrophy in eubacteria. obligate methanotrophy and obligate autotrophy among the chemo- and photo-lithotrophic bacteria lack satisfactory explanation a century or more after their discovery. various causes of these phenomena have been suggested, which we review in the light of the information currently availab ... | 2004 | 15449607 |
| dynamics of a pasture soil microbial community after deposition of cattle urine amended with [13c]urea. | within grazed pastures, urine patches are hot spots of nitrogen turnover, since dietary n surpluses are excreted mainly as urea in the urine. this short-term experiment investigated 13c uptake in microbial lipids after simulated deposition of cattle urine at 10.0 and 17.1 g of urea c m(-2). confined field plots without or with cattle urine amendment were sampled after 4 and 14 days, and soil from 0- to 5-cm and 10- to 20-cm depths was analyzed for content and composition of phospholipid fatty ac ... | 2004 | 15528493 |
| denaturing gradient gel electrophoretic analysis of ammonia-oxidizing bacterial community structure in the lower seine river: impact of paris wastewater effluents. | the seine river is strongly affected by the effluents from the acheres wastewater treatment plant (wwtp) downstream of the city of paris. we have shown that the effluents introduce large amounts of ammonia and inoculate the receiving medium with nitrifying bacteria. the aim of the present study was to investigate the diversity of the ammonia-oxidizing bacterial population by identifying autochthonous bacteria from upstream and/or allochthonous ammonia-oxidizing bacteria from the wwtp effluents. ... | 2004 | 15528539 |
| removal of carbonaceous and nitrogenous pollutants from a synthetic wastewater using a membrane-coupled bioreactor. | two modified ludzack-ettinger (mle)-type membrane-coupled bioreactors (mbrs) were investigated in this study for the purpose of removing both nitrogenous and carbonaceous pollutants from a synthetic wastewater. during the first mbr experiment, removal efficiencies were high (>90%) for chemical oxygen demand (cod) and ammonia, but total nitrogenous pollutant removal efficiency was poor (approximately 25%). bacterial community analysis of ammonia oxidizing bacteria (aob) by a nested pcr-dgge appro ... | 2004 | 15338423 |