| responses of ammonia-oxidizing bacterial and archaeal populations to organic nitrogen amendments in low-nutrient groundwater. | to evaluate the potential for organic nitrogen addition to stimulate the in situ growth of ammonia oxidizers during a field scale bioremediation trial, samples collected from the eastern snake river plain aquifer in idaho before, during, and after the addition of molasses and urea were subjected to pcr analysis of ammonia monooxygenase subunit a (amoa) genes. ammonia-oxidizing bacteria (aob) and archaea (aoa) were present in all of the samples tested, with aoa amoa genes outnumbering aob amoa ge ... | 2010 | 20190081 |
| strategies of nitrosomonas europaea 19718 to counter low dissolved oxygen and high nitrite concentrations. | nitrosomonas europaea is a widely studied chemolithoautotrophic ammonia oxidizing bacterium. while significant work exists on the ammonia oxidation pathway of n. europaea, its responses to factors such as dissolved oxygen limitation or sufficiency or exposure to high nitrite concentrations, particularly at the functional gene transcription level are relatively sparse. the principal goal of this study was to investigate responses at the whole-cell activity and gene transcript levels in n. europae ... | 2010 | 20202220 |
| exploring the relationship between viscous bulking and ammonia-oxidiser abundance in activated sludge: a comparison of conventional and ifas systems. | this study investigated the nature of viscous sludge bulking within a molasses-fed integrated fixed-film activated sludge (ifas) and conventional activated sludge (as) plant by routinely measuring the total carbohydrate and protein fractions of the mixed liquor (ml). the impacts of sludge settleability and plant performance on the relative abundance of ammonia-oxidising bacteria (aob) (nitrosomonas oligotropha-cluster) were also investigated using quantitative polymerase chain reaction (qpcr). r ... | 2010 | 20202664 |
| electron paramagnetic studies of the copper and iron containing soluble ammonia monooxygenase from nitrosomonas europaea. | soluble ammonia monooxygenase (amo) from nitrosomonas europaea was purified to homogeneity and metals in the active sites of the enzyme (cu, fe) were analyzed by electron paramagnetic resonance (epr) spectroscopy. epr spectra were obtained for a type 2 cu(ii) site with g(parallel) = 2.24, a(parallel) = 18.4 mt and g(perpendicular) = 2.057 as well as for heme and non heme iron present in purified soluble amo from n. europaea. a second type 2 cu(ii) epr signal with g(parallel) = 2.29, a(parallel) ... | 2010 | 20204476 |
| nitrifier characteristics in submerged membrane bioreactors under different sludge retention times. | three submerged membrane bioreactors (mbrs) were operated continuously for 230 days by feeding with synthetic inorganic wastewater (nh(4)(+)-n, 100 mg l(-1)) under different solids retention times (srts. m(30d), 30 days; m(90d), 90 days; m(infinite), no sludge purge) to examine the influence of srt on nitrification performance and microbial characteristics. all the reactors could oxidize nh(4)(+)-n to no(3)(-)-n effectively without accumulation of no(2)(-)-n. m(30d) with the shortest srt showed ... | 2010 | 20227741 |
| fast start-up of a pilot-scale deammonification sequencing batch reactor from an activated sludge inoculum. | deammonification involves the combined application of aerobic and anoxic ammonium-oxidizing bacteria (aeraob & anaob) and allows to treat wastewaters with a high ammonium concentration in a sustainable and cost-efficient way. so far, it could take more than one year to start up the process, even with the addition of anaob enriched inocula. in contrast, we started up a deammonifying reactor for the treatment of sludge digestate in less than four months without any anaob enriched inoculum. in a si ... | 2010 | 20351417 |
| [densification of autotrophic bacteria sludge and its characteristics for wastewater treatment]. | autotrophic granular sludge was developed in an sbr reactor using inorganic carbonal substrate. the variation of ammonia-oxidizing bacteria (aob) and nitrite-oxidizing bacteria (nob) during the densification process and their effects on granulation have been evaluated. it was found that the autotrophic bacteria granular sludge was compact with the density reached up to 1.06 g/ml, and the rod-like bacteria predominated in granules on the evidence of scanning electron microscopic (sem) results. am ... | 2010 | 20358836 |
| [cultivation of aerobic granules by a method of alternative feed loading]. | the formation process and morphological and physicochemical properties of aerobic granules were examined in a sbr system by a method of alternative feed loading. the results showed that the aerobic granules could be quickly and effectively cultivated using the alternative feeding cod 400, 800, 1200 mg/l [feed loading 0.96, 1.92 and 3.84 kg/(m3 x d)] when other conditions were fixed. the developed granules of the reactor were maintained in mlss 20-22 g/l and svi 14-16 ml/g. the average size of co ... | 2010 | 20358837 |
| temporal variation in maximum cell-specific nitrification rate. | the cell numbers of ammonia-oxidising bacteria (aobs), nitrospira and nitrobacter in activated sludge used to treat wastewater from a thermal power plant in japan were examined for nine months using a real-time pcr quantification technique. aob cell numbers ranged 2.8 x 10(10)-2.3 x 10(11) cell/l. the amoa clone analysis showed that the only nitrosomonas halophila was responsible for ammonia oxidation over the period. nitrospira were in the range of 2.6 x 10(9)-2.4 x 10(10) cell/l and nitrobacte ... | 2010 | 20389005 |
| characterization and quantification of ammonia-oxidizing archaea (aoa) and bacteria (aob) in a nitrogen-removing reactor using t-rflp and qpcr. | using ammonia monooxygenase alpha-subunit (amoa) gene and 16s rrna gene, the community structure and abundance of ammonia-oxidizing archaea (aoa) and ammonia-oxidizing bacteria (aob) in a nitrogen-removing reactor, which was operated for five phases, were characterized and quantified by cloning, terminal restriction fragment length polymorphism (t-rflp), and quantitative polymerase chain reaction (qpcr). the results suggested that the dominant aob in the reactor fell to the genus nitrosomonas, w ... | 2010 | 20405121 |
| transcription levels (amoa mrna-based) and population dominance (amoa gene-based) of ammonia-oxidizing bacteria. | a population shift of ammonia-oxidizing bacteria (aob) was described within a bench-scale activated sludge process treating an industrial wastewater in a previous report (kuo et al. in environ eng sci 23:507-520, 2006). in this investigation, transcriptional levels (amoa mrna-based) of the three aob groups (i.e., ri-27, b2-3, and nitrosomonas nitrosa) identified in the treatment process were determined by quantitative real-time reverse transcription (rt-pcr) assays to circuitously evaluate aob a ... | 2010 | 20440533 |
| microbial community structure and occurrence of diverse autotrophic ammonium oxidizing microorganisms in the anammox process. | the enrichment of anaerobic ammonium oxidizing (anammox) bacteria using an upflow anaerobic sludge bioreactor was successfully conducted for 400 days of continuous operation. the bacterial community structure of anammox bioreactor included proteobacteria (42%), chloroflexi (22%), planctomycetes (20%), chlorobi (7%), bacteroidetes (5%), acidobacteria (2%), and actinobacteria (2%). all clones of planctomycetes were affiliated with the anammox bacteria, planctomycete ksu-1 (ab057453). the presence ... | 2010 | 20489244 |
| diversity, abundance, and spatial distribution of sediment ammonia-oxidizing betaproteobacteria in response to environmental gradients and coastal eutrophication in jiaozhou bay, china. | ongoing anthropogenic eutrophication of jiaozhou bay offers an opportunity to study the influence of human activity on bacterial communities that drive biogeochemical cycling. nitrification in coastal waters appears to be a sensitive indicator of environmental change, suggesting that function and structure of the microbial nitrifying community may be associated closely with environmental conditions. in the current study, the amoa gene was used to unravel the relationship between sediment aerobic ... | 2010 | 20511433 |
| co-occurrence of nitrogen-converting organisms in full-scale treatment plants. | this study provides insights into nitrogen-converting microorganisms in three full-scale wastewater treatment plants (wwtps), which were investigated and monitored according to their nitrification performance and the presence of ammonia-oxidizing bacteria (aob), nitrite-oxidizing bacteria (nob), ammonia-oxidizing archaea (aoa), and anammox bacteria based on different molecular tools: fluorescent in situ hybridization (fish), slot-blot hybridization, and quantitative real-time pcr. in situ hybrid ... | 2010 | 20535877 |
| inoculum effects on community composition and nitritation performance of autotrophic nitrifying biofilm reactors with counter-diffusion geometry. | the link between nitritation success in a membrane-aerated biofilm reactor (mabr) and the composition of the initial ammonia- and nitrite-oxidizing bacterial (aob and nob) population was investigated. four identically operated flat-sheet type mabrs were initiated with two different inocula: from an autotrophic nitrifying bioreactor (inoculum a) or from a municipal wastewater treatment plant (inoculum b). higher nitritation efficiencies (no(2)(-)-n/nh(4)(+)-n) were obtained in the inoculum b- (55 ... | 2010 | 20545751 |
| stresses exerted by zno, ceo2 and anatase tio2 nanoparticles on the nitrosomonas europaea. | recent studies have shown that nano-bio interfaces are the most complex and the least understood. notably, nanotoxicity of these nanoparticles is not even well recognized. in this work, we examined the toxic effects of different nanoparticles on bacteria cells (nitrosomonas europaea). the four nanoparticles involved are: 25 nm anatase tio(2), 200 nm anatase tio(2), zno and ceo(2) particles. these particles will have different electrical charges in the cell cultivating media. it has been observed ... | 2010 | 20546765 |
| short-term effect of ammonia concentration and salinity on activity of ammonia oxidizing bacteria. | a continuously aerated sharon (single reactor high activity ammonia removal over nitrite) system has been operated to achieve partial nitritation. two sets of batch experiments were carried out to study the effect of ammonia concentration and salinity on the activity of ammonia-oxidizing bacteria (aob). activity of aob raised as free ammonia concentration was increased reaching its maximum value at 4.5 mg nh3-n l(-1). the half saturation constant for free ammonia was determined (k(nh3)=0.32 mg n ... | 2010 | 20555196 |
| diversity of nitrifying bacteria in a full-scale petroleum refinery wastewater treatment plant experiencing unstable nitrification. | we have investigated bacterial populations relevant to nitrification in a full-scale activated sludge plant receiving wastewater from a petroleum refinery showing unstable nitrification. inhibition of ammonia oxidation was related to phenol concentration according to a model of non-competitive inhibition. while the number of ammonia-oxidizing bacteria (aob) did not correlate with nitrification performance, the total number of nitrite-oxidizing bacteria (nob) dropped considerably during periods o ... | 2010 | 20570044 |
| diversity and abundance of ammonia-oxidizing bacteria and ammonia-oxidizing archaea during cattle manure composting. | ammonia-oxidizing bacteria (aob) and ammonia-oxidizing archaea (aoa) play important roles in nitrification in various environments. they may also be key communities for ammonia oxidation in composting systems, although few studies have discussed their presence. we investigated the relative diversity and abundance of aob and aoa using cloning procedures, denaturing gradient gel electrophoresis analysis, and real-time pcr during several stages in the process of cattle manure composting. our result ... | 2010 | 20607531 |
| effect of substrate cod/n ratio on performance and microbial community structure of a membrane aerated biofilm reactor. | two parallel carbon-membrane aerated biofilm reactors were operated at well-defined conditions to investigate the effect of substrate cod/n ratios on the performance and microbial community structure of the bioreactor. results showed that at substrate cod/n of 5, organic and nitrogen could be eliminated simultaneously, and cod removal degree, nitrification and denitrification efficiency reached 85%, 93% and 92%, respectively. with increasing substrate cod/n ratios, the specific oxygen utilizatio ... | 2010 | 20617730 |
| community analysis of ammonia-oxidizing bacteria in activated sludge of eight wastewater treatment systems. | we investigated the communities of ammonia-oxidizing bacteria (aob) in activated sludge collected from eight wastewater treatment systems using polymerase chain reaction (pcr) followed by terminal restriction fragment length polymorphism (t-rflp), cloning, and sequencing of the alpha-subunit of the ammonia monooxygenase gene (amoa). the t-rflp fingerprint analyses showed that different wastewater treatment systems harbored distinct aob communities. however, there was no remarkable difference amo ... | 2010 | 20617742 |
| the behavior of nitrifying sludge in presence of sulfur compounds using a floating biofilm reactor. | the tolerance, kinetic and oxidizing capability of a nitrifying sludge exposed to different initial concentrations of sulfide (1.7 to 18mg/l) was evaluated in batch experiments. a nitrifying sludge fed with ammonium and thiosulfate and produced in steady state conditions was used as inoculum. sulfide induced a significant effect either on ammonium consumption rates or nitrite accumulation. in spite of the nitrifying kinetic was affected, the ammonium consumption efficiencies were close to 100%, ... | 2010 | 20620047 |
| microbial community distribution and activity dynamics of granular biomass in a canon reactor. | the application of microelectrodes to measure oxygen and nitrite concentrations inside granules operated at 20 degrees c in a canon (complete autotrophic nitrogen-removal over nitrite) reactor and the application of the fish (fluorescent in situ hybridization) technique to cryosectioned slices of these granules showed the presence of two differentiated zones inside of them: an external nitrification zone and an internal anammox zone. the fish analysis of these layers allowed the identification o ... | 2010 | 20646732 |
| characterization of bacterial structures in two-stage moving-bed biofilm reactor (mbbr) during nitrification of the landfill leachate. | differences in dna banding patterns, obtained by ribosomal intergenic spacer analysis (risa), and nitrification were followed in a moving-bed biofilm reactor (mbbr) receiving municipal landfill leachate. complete nitrification (> 99%) to nitrate was obtained in the two-stage mbbr system with an ammonium load of 1.09 g n-nh(4)/m(2).d. increasing the ammonium load to 2.03 g n-nh(4)/m(2).d or more caused a decline in process efficiency to 70-86%. moreover, at the highest ammonium load (3.76 g n-nh( ... | 2010 | 20668409 |
| [effects of rice straw on the diversity of nitrifying genes (amoa and hao) in paddy soil]. | the effects of long-term (16 years) fertilization on the diversity and community structure of soil ammonia-oxidizing gene (amoa) and hydroxylamine-oxidizing gene (hao) in paddy soil were evaluated using the methods of polymerase chain reaction, cloning and sequencing. the soil samples were collected from the treatments of npk (ck) and npk plus rice straw (sr) of the long-term field fertilization experiment in taoyuan agro-ecological experimental station. the shannon indices showed that the diver ... | 2010 | 20698282 |
| membrane-aerated biofilm proton and oxygen flux during chemical toxin exposure. | bioreactors containing sessile bacteria (biofilms) grown on hollow fiber membranes have been used for treatment of many wastestreams. real time operational control of bioreactor performance requires detailed knowledge of the relationship between bulk liquid water quality and physiological transport at the biofilm-liquid interface. although large data sets exist describing membrane-aerated bioreactor effluent quality, very little real time data is available characterizing boundary layer transport ... | 2010 | 20735036 |
| role of nitrosomonas europaea nitabc iron transporter in the uptake of fe3+-siderophore complexes. | nitrosomonas europaea has a single three-gene operon (nitabc) encoding an iron abc transporter system (nitabc). phylogenetic analysis clustered the subunit nitb with fe(3+)-abc transporter permease components from other organisms. the n. europaea strain deficient in nitb (nitb::kan) grew well in either fe-replete or fe-limited media and in fe-limited medium containing the catecholate-type siderophore, enterobactin or the citrate-based dihydroxamate-type siderophore, aerobactin. however, the nitb ... | 2010 | 20737137 |
| estimation of nitrifier abundances in a partial nitrification reactor treating ammonium-rich saline wastewater using dgge, t-rflp and mathematical modeling. | the bacterial community in a partial nitrification reactor was analyzed on the basis of 16s rrna gene by cloning-sequencing method, and the percentages of ammonia-oxidizing bacteria (aob) and nitrite-oxidizing bacteria (nob) in the activated sludge were quantified by three independent methods, namely, denaturing gradient gel electrophoresis (dgge), terminal restriction fragment length polymorphism (t-rflp) and double monod modeling. the clone library results suggested that there were only a domi ... | 2010 | 20737268 |
| comparison of the effects of different salts on aerobic ammonia oxidizers for treating ammonium-rich organic wastewater by free and sodium alginate immobilized biomass system. | partial nitrification to nitrite by aerobic ammonium oxidizing bacteria (aob) is an important pre-treatment step for subsequent denitrification and anammox. ammonium-rich wastewater may contain different amounts of organic matter and salts, which can influent the growth and activity of aob significantly. in this study we investigated the influence of various salts on the performance of a partial nitrification process with free and sodium alginate immobilized biomass. immobilization of the aob ce ... | 2010 | 20797762 |
| enzymatic interconversion of ammonia and nitrite: the right tool for the job. | hydroxylamine oxidoreductase (hao) from nitrosomonas europaea normally catalyzes oxidation of nh(2)oh to no(2)(-). this paper reports experiments in which hao was thermodynamically poised to catalyze reduction of no(2)(-) to nh(4)(+). hao was found to catalyze the reduction of no(2)(-) by methyl viologen monocation radical (mv(red)), displaying a hyperbolic dependence on no(2)(-) concentration, with a k(cat1) of 6.8 ± 0.3 s(-1) and a k(m1) of 7.6 ± 0.9 mm. hao also catalyzed the reduction of nh( ... | 2010 | 20812758 |
| potentials of mean force and permeabilities for carbon dioxide, ammonia, and water flux across a rhesus protein channel and lipid membranes. | as a member of the ubiquitous ammonium transporter/methylamine permease/rhesus (amt/mep/rh) family of membrane protein channels, the 50 kda rhesus channel (rh50) has been implicated in ammonia (nh(3)) and, more recently, also in carbon dioxide (co(2)) transport. here we present molecular dynamics simulations of spontaneous full permeation events of ammonia and carbon dioxide across rh50 from nitrosomonas europaea. the simulations show that rh50 is functional in its crystallographic conformation, ... | 2010 | 20815391 |
| computational prediction and transcriptional analysis of srnas in nitrosomonas europaea. | bacterial small noncoding rnas (srnas) have been discovered in many genetically well-studied microorganisms and have been shown to regulate critical cellular processes at the post-transcriptional level. in this study, we used comparative genomics and microarray data to analyze the genome of the ammonia-oxidizing bacterium nitrosomonas europaea for the presence and expression of srnas. fifteen genes encoding putative srnas (psrnas) were identified. most of these genes showed altered expression in ... | 2010 | 20840601 |
| response of nitrifying bacterial communities to the increased thiocyanate concentration in pre-denitrification process. | changes in process performance and the nitrifying bacterial community associated with an increase of thiocyanate (scn-) loading were investigated in a pre-denitrification process treating industrial wastewater. the increased scn- loading led to the concentration of total nitrogen (tn) in the final effluent, but increasing the internal recycling ratio as an operation parameter from 2 to 5 resulted in a 21% increase in tn removal efficiency. in the aerobic reactor, we found that the nitrosomonas e ... | 2010 | 20933392 |
| bioaugmentation of a biological contact oxidation ditch with indigenous nitrifying bacteria for in situ remediation of nitrogen-rich stream water. | in this study, specialized bacteria were domesticated and cultivated with polluted stream water. the bioaugmentation of specialized bacteria would significantly enhance the removal efficiency of tn and nh4+-n from 25.9% to 50.3%, and from 34.5% to 60.1%, respectively. concomitant increases in the number of microbial communities and the proportion of nitrifying bacteria were also identified by the most probable number (mpn) method. pcr-dgge profiles revealed that the bacterial community could be ... | 2010 | 20943379 |
| structure of the first representative of pfam family pf09410 (duf2006) reveals a structural signature of the calycin superfamily that suggests a role in lipid metabolism. | the first structural representative of the domain of unknown function duf2006 family, also known as pfam family pf09410, comprises a lipocalin-like fold with domain duplication. the finding of the calycin signature in the n-terminal domain, combined with remote sequence similarity to two other protein families (pf07143 and pf08622) implicated in isoprenoid metabolism and the oxidative stress response, support an involvement in lipid metabolism. clusters of conserved residues that interact with l ... | 2010 | 20944205 |
| determination of the effects of medium composition on the monochloramine disinfection kinetics of nitrosomonas europaea by the propidium monoazide quantitative pcr and live/dead baclight methods. | various medium compositions (phosphate, 1 to 50 mm; ionic strength, 2.8 to 150 meq/liter) significantly affected nitrosomonas europaea monochloramine disinfection kinetics, as determined by the live/dead baclight (ld) and propidium monoazide quantitative pcr (pma-qpcr) methods (lag coefficient, 37 to 490 [ld] and 91 to 490 [pma-qpcr] mg·min/liter; chick-watson rate constant, 4.0 × 10(-3) to 9.3 × 10(-3) [ld] and 1.6 × 10(-3) to 9.6 × 10(-3) [pma-qpcr] liter/mg·min). two competing effects may acc ... | 2010 | 20952645 |
| induced cooperation between marine nitrifiers and anaerobic ammonium-oxidizing bacteria by incremental exposure to oxygen. | in oxygen-limited marine ecosystems cooperation between marine nitrifiers and anaerobic ammonium-oxidizing (anammox) bacteria is of importance to nitrogen cycling. strong evidence for cooperation between anammox bacteria and nitrifiers has been provided by environmental studies but little is known about the development of such communities, the effects of environmental parameters and the physiological traits of their constituents. in this study, a marine laboratory model system was developed. coo ... | 2010 | 20956064 |
| a control strategy of partial nitritation in a fixed bed biofilm reactor. | to achieve an appropriate mixture of ammonium and nitrite for anaerobic ammonium oxidation (anammox), 50% partial nitritation was optimized in a fixed bed biofilm reactor treating synthetic wastewater. results suggested that 50% partial nitritation could be achieved by stepwise increases of influent nh4+-n at ph of 7.8±0.2, temperature of 30±1°c and dissolved oxygen (do) of 0.5-0.8 mg l(-1). hydraulic retention time (hrt) and influent alkalinity did significantly affect partial nitritation. at h ... | 2010 | 20971638 |
| identification and quantitative evaluation of nitrogen-converting organisms in a full-scale leachate treatment plant. | the presence of ammonia nitrogen in landfill leachates poses a significant problem for treatment plant operators. the nitrification-denitrification process mostly carries out the nitrogen conversion in biological treatment systems. however, recent research shows that other processes by anaerobic ammonia-oxidizing bacteria (anammox) and ammonia-oxidizing archaea (aoa) were also responsible for the removal of nitrogen in biological systems. in this study, the nitrogen-converting microorganisms in ... | 2010 | 20974516 |
| effects of selected pharmaceutically active compounds on the ammonia oxidizing bacterium nitrosomonas europaea. | pharmaceutically active compounds (phacs) are commonly found in wastewater influent. however, little research has focused on determining their impact on fundamental processes in wastewater treatment such as nitrogen removal. in this study, focus was placed on 4 commonly occurring phacs (ketoprofen, naproxen, carbamazepine and gemfibrozil). their effect was ascertained in the ammonia oxidizing bacterium (aob), nitrosomonas europaea in terms of membrane integrity and nitrite production. these phac ... | 2010 | 20980043 |
| copper toxicity to bioluminescent nitrosomonas europaea in soil is explained by the free metal ion activity in pore water. | the terrestrial biotic ligand model (blm) for metal toxicity in soil postulates that metal toxicity depends on the free metal ion activity in solution and on ions competing for metal sorption to the biotic ligand. unequivocal evidence for the blm assumptions is most difficult to obtain for native soil microorganisms because the abiotic and biotic compartments cannot be experimentally separated. here, we report copper (cu) toxicity to a bioluminescent nitrosomonas europaea reporter strain that wa ... | 2010 | 21047118 |
| effects of free cyanide on microbial communities and biological carbon and nitrogen removal performance in the industrial activated sludge process. | the changes in process performance and microbial communities under free cyanide (cn(-)) were investigated in a lab-scale activated sludge process treating industrial wastewater. the performance of phenol degradation did not appear to be adversely affected by increases in cn(-) concentrations. in contrast, cn(-) was found to have an inhibitory effect on scn(-) biodegradation, resulting in the increase of toc and cod concentrations. nitratation also appeared to be inhibited at cn(-) concentrations ... | 2010 | 21047665 |
| spatial variability in nitrification rates and ammonia-oxidizing microbial communities in the agriculturally impacted elkhorn slough estuary, california. | ammonia oxidation-the microbial oxidation of ammonia to nitrite and the first step in nitrification-plays a central role in nitrogen cycling in coastal and estuarine systems. nevertheless, questions remain regarding the connection between this biogeochemical process and the diversity and abundance of the mediating microbial community. in this study, we measured nutrient fluxes and rates of sediment nitrification in conjunction with the diversity and abundance of ammonia-oxidizing archaea (aoa) a ... | 2010 | 21057023 |
| [comparative analysis of primer-based pcr strategies for characterizing ammonia-oxidizing bacterial communities in lake sediments]. | pcr-based techniques are commonly used to characterize ammonia-oxidizing bacterial (aob) communities, but are subjected to the bias induced by pcr primers. in this study, the sensitivity and specificity of two pairs of primer were assessed based on a group of lake sediment samples. compared to the low sensitivity of the cto primer, the betaamo primer produced intensive single bands in all samples tested. however, the sequences retrieved from one of the samples by betaamo did not cluster with nit ... | 2010 | 21072943 |
| partial nitritation and anammox of a livestock manure digester liquor and analysis of its microbial community. | a swim-bed reactor for partial nitritation with polymeric coagulant treatment and an uasb reactor for anammox were applied to the treatment of livestock manure digester liquor. the partial nitritation was maintained for 32 days under a 1.6 kg n/m(3)/d nitrogen loading rate (nlr) with an average conversion efficiency of 51%, and achieved 1.65 kg n/m(3)/d of the maximum nitrite production rate under 2.58 kg n/m(3)/d of nlr. although 200 mg/l of toc remained in the effluent of the partial nitritati ... | 2010 | 21074422 |
| inhibition and gene expression of nitrosomonas europaea biofilms exposed to phenol and toluene. | pure culture biofilms of the ammonia-oxidizing bacterium nitrosomonas europaea were grown in a drip flow biofilm reactor and exposed to the aromatic hydrocarbons phenol and toluene. ammonia oxidation rates, as measured by nitrite production in the biofilms, were inhibited 50% when exposed to 56 µm phenol or 100 µm toluene, while 50% inhibition of suspended cells occurred at 8 µm phenol or 20 µm toluene. biofilm-grown cells dispersed into liquid medium and immediately exposed to phenol or toluene ... | 2010 | 21077109 |
| linking ne1545 gene expression with cell volume changes in nitrosomonas europaea cells exposed to aromatic hydrocarbons. | nitrosomonas europaea, a model ammonia oxidizing bacterium, was exposed to a wide variety of aromatic hydrocarbons in 3 h batch assays. the expression of ne1545, a phenol sentinel gene involved in fatty acid metabolism, was monitored via quantitative real-time polymerase chain reaction (qrt-pcr) and a coulter counter technique was used to monitor changes in cell volume. decreases in cell volume and ne1545 gene expression correlated strongly with exposure to aromatic hydrocarbons that possessed a ... | 2010 | 21106218 |
| seasonal variations of nitrifying community in trickling filter-solids contact (tf/sc) activated sludge systems. | two full-scale trickling filter/solids contact (tf/sc) basin plants, each successfully performing nitrification, were sampled throughout various seasons over a period of one year. concentrations of ammonia, nitrate and nitrite were measured at various sampling locations along the treatment train. dna was also extracted from mixed liquor in the solids contact basins. these dna samples were subjected to terminal restriction fragment length polymorphism (trflp) in order to profile the ammonia oxidi ... | 2010 | 21112210 |
| biodiversity and population dynamics of microorganisms in a full-scale membrane bioreactor for municipal wastewater treatment. | the total, ammonia-oxidizing, and denitrifying bacteria in a full-scale membrane bioreactor (mbr) were evaluated monthly for over one year. microbial communities were analyzed by denaturing gradient gel electrophoresis (dgge) and clone library analysis of the 16s rrna and ammonia monooxygenase (amoa) and nitrous oxide reductase (nosz) genes. the community fingerprints obtained were compared to those from a conventional activated sludge (cas) process running in parallel treating the same domestic ... | 2010 | 21112606 |
| extracellular dna is abundant and important for microcolony strength in mixed microbial biofilms. | a new approach for quantification of extracellular dna (edna) in mixed biofilms at microscale resolution was developed and combined with other staining techniques to assess the origin, abundance and role of edna in activated sludge biofilms. most edna was found in close proximity to living cells in microcolonies, suggesting that most of it originated from an active secretion or alternatively, by lysis of a sub-population of cells. when the staining was combined with fluorescence in situ hybridiz ... | 2010 | 21118344 |
| nitrogen removal from wastewater using membrane aerated microbial fuel cell techniques. | nitrogen removal mainly relies on sequential nitrification and denitrification in wastewater treatment. microbial fuel cells (mfcs) are innovative wastewater treatment techniques for pollution control and energy generation. in this study, bench-scale wastewater treatment systems using membrane-aerated mfc (mamfc) and diffuser-aerated mfc (damfc) techniques were constructed for simultaneous removal of carbonaceous and nitrogenous pollutants and electricity production from wastewater. during 210 d ... | 2010 | 21131019 |
| quantitative proteomic analysis of the chemolithoautotrophic bacterium nitrosomonas europaea: comparison of growing- and energy-starved cells. | obligately aerobic ammonia-oxidizing bacteria (aob) like nitrosomonas europaea play a pivotal role in the global nitrogen cycle. although starvation tolerance is a key environmental adaptation, little is known about this response in aob. the goal of these studies was to compare the composition of the n. europaea proteome in growing- and energy-starved cells using ¹⁵n labeling and hplc-esi-ms/ms. more than 6500 peptides were sequenced with high confidence, and matched to 876 proteins (34% of the ... | 2010 | 21172464 |
| rapid and sensitive nitrosomonas europaea biosensor assay for quantification of bioavailable ammonium sensu strictu in soil. | knowledge on bioavailable ammonium sensu strictu (i.e., immediately available for cellular uptake) in soil is required to understand nutrient uptake processes in microorganisms and thus of vital importance for plant production. we here present a novel ammonium biosensor approach based on the lithoautotrophic ammonia-oxidizing bacterium nitrosomonas europaea transformed with a luxab sensor plasmid. bioluminescence-based ammonium detection was achieved within 10 min with a quantification limit in ... | 2010 | 21174468 |
| structure and dynamics of nitrifier populations in a full-scale submerged membrane bioreactor during start-up. | changes of microbial characteristics in a full-scale submerged membrane bioreactor system (capacity, 60,000 m(3) day(-1)) treating sewage were monitored over the start-up period (96 days). fluorescence in situ hybridization analysis showed that the percentages of ammonia-oxidizing bacteria (aob) and nitrite-oxidizing bacteria (nitrobacter-related population) in total bacteria counted with dapi staining increased significantly from 1.9% and 0.9% to 4.5% and 2.8%, corresponding to an increase of t ... | 2010 | 21181155 |
| isolation, cultivation, and characterization of ammonia-oxidizing bacteria and archaea adapted to low ammonium concentrations. | ammonia-oxidizing microorganisms (aom) generate their energy by the oxidation of ammonia (nh(3)) to nitrite (no(2)(-)). this process can be carried out by ammonia-oxidizing bacteria (aob) as well as by the recently discovered ammonia-oxidizing archaea (aoa). in the past, aob were enriched in batch cultures, often in the presence of rather high concentrations of nh(4)(+). here, we describe methods to enrich, isolate, and investigate the basic physiology of aob and aoa with emphasis on those that ... | 2011 | 21185431 |
| measuring nitrification, denitrification, and related biomarkers in terrestrial geothermal ecosystems. | research on the nitrogen biogeochemical cycle in terrestrial geothermal ecosystems has recently been energized by the discovery of thermophilic ammonia-oxidizing archaea (aoa). this chapter describes methods that have been used for measuring nitrification and denitrification in hot spring environments, including isotope pool dilution and tracer approaches, and the acetylene block approach. the chapter also summarizes qualitative and quantitative methods for measurement of functional and phylogen ... | 2011 | 21185436 |
| assessment of nitrogen and oxygen isotopic fractionation during nitrification and its expression in the marine environment. | nitrification is a microbially-catalyzed process whereby ammonia (nh(3)) is oxidized to nitrite (no(2)(-)) and subsequently to nitrate (no(3)(-)). it is also responsible for production of nitrous oxide (n(2)o), a climatically important greenhouse gas. because the microbes responsible for nitrification are primarily autotrophic, nitrification provides a unique link between the carbon and nitrogen cycles. nitrogen and oxygen stable isotope ratios have provided insights into where nitrification con ... | 2011 | 21185439 |
| regulation and measurement of nitrification in terrestrial systems. | understanding nitrification rates and their regulation continues as a key area of research for assessing human's increasing impact on the terrestrial n cycle. we review the organisms and processes responsible for nitrification in terrestrial systems. the control of nitrification by substrate availability is discussed with particular attention to the factors affecting ammonia/ammonium availability. the effects on nitrification rates of environmental controls including oxygen, water potential, tem ... | 2011 | 21185443 |
| genetic transformation of ammonia-oxidizing bacteria. | the study of traits of ammonia-oxidizing bacteria (aob) by genetic transformation is an approach that is facilitated by the availability of aob genome sequences. to transform an aob, a vector construct is introduced into the cells by electroporation or conjugation to effect the inactivation, complementation, or expression of a selected gene. for inactivation studies, the vector construct should contain the gene of interest with an antibiotic resistance cassette and recombine into the cell's chro ... | 2011 | 21185445 |
| dissecting iron uptake and homeostasis in nitrosomonas europaea. | the chemolithoautotroph nitrosomonas europaea oxidizes about 25 mol of nh(3) for each mole of co(2) that is converted to biomass using an array of heme and nonheme fe-containing proteins. hence mechanisms of efficient iron (fe) uptake and homeostasis are particularly important for this betaproteobacterium. among nitrifiers, n.europaea has been the most studied to date. characteristics that make n.europaea a suitable model to study fe uptake and homeostasis are as follows: (a) its sequenced genom ... | 2011 | 21185446 |
| liquid chromatography-mass spectrometry-based proteomics of nitrosomonas. | during the last century, the research on aerobic ammonium-oxidizing bacteria (aob) lead to many exciting physiological and biochemical discoveries. nevertheless the molecular biology of aob is not well understood. the availability of the genome sequences of several nitrosomonas species opened up new possiblities to use state of the art transcriptomic and proteomic tools to study aob. with the currect technology, thousands of proteins can be analyzed in several hours of measurement and translated ... | 2011 | 21185449 |
| experimental and theoretical examination of surface energy and adhesion of nitrifying and heterotrophic bacteria using self-assembled monolayers. | biofilm-based systems, including integrated fixed-film activated sludge and moving bed bioreactors, are becoming increasingly popular for wastewater treatment, often with the goal of improving nitrification through the enrichment of ammonia and nitrite oxidizing bacteria. we have previously demonstrated the utility of self-assembled monolayers (sams) as tools for studying the initial attachment of bacteria to substrata systematically varying in physicochemical properties. in this work, we expand ... | 2010 | 21189005 |
| nitrosococcus watsonii sp. nov., a new species of marine obligate ammonia-oxidizing bacteria that is not omnipresent in the world's oceans: calls to validate the names 'nitrosococcus halophilus' and 'nitrosomonas mobilis'. | local associations between anammox bacteria and obligate aerobic bacteria in the genus nitrosococcus appear to be significant for ammonia oxidation in oxygen minimum zones. the literature on the genus nitrosococcus in the chromatiaceae family of purple sulfur bacteria (gammaproteobacteria, chromatiales) contains reports on four described species, nitrosococcus nitrosus, nitrosococcus oceani, 'nitrosococcus halophilus' and 'nitrosomonas mobilis', of which only n. nitrosus and n. oceani are validl ... | 2011 | 21204874 |
| comparison of the community structures of ammonia-oxidizing bacteria and archaea in rhizoplanes of floating aquatic macrophytes. | some common floating aquatic macrophytes could remove nutrients, such as nitrogen, from eutrophic water. however, the relationship between these macrophytes and the ammonia-oxidizing microorganisms on their rhizoplanes is still unknown. in this study, we examined communities of ammonia-oxidizing archaea (aoa) and bacteria (aob) on the rhizoplanes of common floating aquatic macrophytes (eichhornia crassipes, pistia stratiotes and ipomoea aquatic) in a eutrophic reservoir.the results show that aob ... | 2011 | 21239153 |
| [screening and nitrogen transformation activity of ammonia-oxidizing molds during aerobic chicken manure composting]. | in order to explicit the existence and nitrogen transformation activity of ammonia-oxidizing molds during aerobic chicken manure composting, the medium of ammonia-oxidizing molds was used to screen them, and correlation analysis between mycelium biomass and nitrogen transformation indexes was conducted, then high-effective ammonia-oxidizing strains were determined and added into aerobic compost. the results show that all tested strains are able to oxidize ammonium nitrogen to nitrite nitrogen an ... | 2010 | 21250463 |
| ammonia-oxidizing bacteria in biofilters removing trihalomethanes are related to nitrosomonas oligotropha. | ammonia-oxidizing bacteria (aob) in nitrifying biofilters degrading four regulated trihalomethanes-trichloromethane, bromodichloromethane, dibromochloromethane, and tribromomethane-were related to nitrosomonas oligotropha. n. oligotropha is associated with chloraminated drinking water systems, and its presence in the biofilters might indicate that trihalomethane tolerance is another reason that this bacterium is dominant in chloraminated systems. | 2011 | 21278264 |
| theoretical simulation of the spectroscopy and dynamics of a red copper protein. | the electronic absorption, circular dichroism and x-ray absorption spectroscopy of the red copper protein nitrosocyanin is simulated with classical molecular dynamics simulations in conjunction with time-dependent density functional theory (tddft) and multireference configuration interaction (mrci) calculations on the active site, with the remainder of the protein and solvent included via point charges. in the molecular dynamics simulations of the oxidised form of the protein an exogenous water ... | 2011 | 21322477 |
| the community analysis of ammonia-oxidizing bacteria in wastewater treatment plants revealed by the combination of double labeled t-rflp and sequencing. | the functional gene of amoa, which produces the a-subunit of ammonia monooxygenase (amo), has been analyzed to reveal the microbial community structure of ammonia-oxidizing bacteria (aob) by culture-independent methods. in this study, the distribution of the amoa gene in 10 wastewater treatment plants (wwtps) was revealed by the fingerprinting method of terminal restriction fragment length polymorphism (t-rflp) and comparative sequencing. t-rflp showed diverse communities of aob in the modified ... | 2011 | 21337248 |
| role of a fur homolog in iron metabolism in nitrosomonas europaea. | in response to environmental iron concentrations, many bacteria coordinately regulate transcription of genes involved in iron acquisition via the ferric uptake regulation (fur) system. the genome of nitrosomonas europaea, an ammonia-oxidizing bacterium, carries three genes (ne0616, ne0730 and ne1722) encoding proteins belonging to fur family. | 2011 | 21338516 |
| inhibition and gene expression of nitrosomonas europaea biofilms exposed to phenol and toluene. | pure culture biofilms of the ammonia-oxidizing bacterium nitrosomonas europaea were grown in a drip flow biofilm reactor and exposed to the aromatic hydrocarbons phenol and toluene. ammonia oxidation rates, as measured by nitrite production in the biofilms, were inhibited 50% when exposed to 56 µm phenol or 100 µm toluene, while 50% inhibition of suspended cells occurred at 8 µm phenol or 20 µm toluene. biofilm-grown cells dispersed into liquid medium and immediately exposed to phenol or toluene ... | 2010 | 21404249 |
| [analysis of the changes of microbial community structure on bio-carrier of recirculating aquaculture systems (ras)]. | in order to study the variation of microbial community structure and the mechanism of denitrification on bio-carrier in recirculating aquaculture systems (ras) during the periods of bio-film formation and operation the systems, traditional microbiological methods were applied to count the quantity of heterotrophic bacteria, ammonia oxidize bacteria and nitrite oxidize bacteria. the amplified products of variable v3 region of bacterial 16s rdna were separated by using denaturing gradient gel elec ... | 2011 | 21404692 |
| nitrifying bacterial community structure of a full-scale integrated fixed-film activated sludge process as investigated by pyrosequencing. | nitrifying bacterial community structures of suspended and attached biomasses in a full-scale integrated fixed-film activated sludge process were investigated by analyzing 16s rrna gene sequences obtained from pyrosequencing. the suspended biomass had a higher number of ammoniaoxidizing bacterial sequences (0.8% of total sequences) than the attached biomass (0.07%), although most of the sequences were within the nitrosomonas oligotropha lineage in both biomasses. nitrospira-like nitrite-oxidizin ... | 2011 | 21464601 |
| [diversity of beta-proteobacterial ammonia-oxidizing bacteria and ammonia-oxidizing archaea in shrimp farm sediment]. | in order to study the diversity of ammonia-oxidizing bacteria (aob) and ammonia-oxidizing archaea (aoa) in shrimp farm sediment. | 2011 | 21465792 |
| investigation of nitrogen converters in membrane bioreactor. | in this study, the activity and diversity of nitrogen converters, ammonia-oxidizing bacteria (aob) and nitrite-oxidizing bacteria (nob), ammonia-oxidizing archaea (aoa) and anammox bacteria in a pilot-scale membrane bioreactor (mbr) were investigated and monitored using amoa and 16s rdna-based molecular tools. the pilot-scale mbr (100 m(3)/day) was located inside the full-scale pasakoy advanced wastewater treatment plant (wwtp), and operated for approximately 5 months without sludge purge. durin ... | 2011 | 21469010 |
| effects of nitrite on ammonia-oxidizing activity and gene regulation in three ammonia-oxidizing bacteria. | nitrite is the highly toxic end product of ammonia oxidation that accumulates in the absence of a nitrite-consuming process and is inhibitory to nitrifying and other bacteria. the effects of nitrite on ammonia oxidation rates and regulation of a common gene set were compared in three ammonia-oxidizing bacteria (aob) to determine whether responses to this toxic metabolite were uniform. mid-exponential-phase cells of nitrosomonas europaea atcc 19718, nitrosospira multiformis atcc 25196, and nitros ... | 2011 | 21470297 |
| bacterial community structure of a full-scale biofilter treating pig house exhaust air. | biological air filters represent a promising tool for treating emissions of ammonia and odor from pig facilities. quantitative fluorescence in situ hybridization (fish) and 16s rrna gene sequencing were used to investigate the bacterial community structure and diversity in a full-scale biofilter consisting of two consecutive compartments (front and back filter). the analysis revealed a highly specialized bacterial community of limited diversity, dominated by a few groups of betaproteobacteria (e ... | 2011 | 21514081 |
| investigating nitrosomonas europaea stress biomarkers in batch, continuous culture, and biofilm reactors. | the understanding of nitrification inhibition in ammonia oxidizing bacteria (aob) by priority pollutants and emerging contaminants is critical in managing the nitrogen cycle to preserve current water supplies, one of the national academy of engineers grand challenges in engineering for the twenty-first century. nitrosomonas europaea is an excellent model aob for nitrification inhibition experimentation due to its well-defined nh(3) metabolism and the availability of a wide range of physiological ... | 2011 | 21514466 |
| genomics for key players in the n cycle from guinea pigs to the next frontier. | while sequencing methods were available in the late 1970s, it was not until the human genome project and a significant influx of funds for such research that this technology became high throughput. the fields of microbiology and microbial ecology, among many others, have been tremendously impacted over the years, to such an extent that the determination of complete microbial genome sequences is now commonplace. given the lower costs of next-generation sequencing platforms, even small laboratorie ... | 2011 | 21514469 |
| detection and characterization of a multicopper oxidase from nitrosomonas europaea. | blue copper oxidase (bco) is a multicopper oxidase (mco) found in nitrosomonas europaea as well as in other ammonia-oxidizing organisms. in this chapter, we detail methods used to detect, isolate, and characterize bco from n. europaea. a method for identifying and classifying mcos commonly found in nitrifiers based on primary sequence is also described. | 2011 | 21514474 |
| assessing variability in gel-based proteomic analysis of nitrosomonas europaea. | proteomics offers a unique look at the way protein expression changes in response to stimuli, and "gel-based" methods that utilize two-dimensional gel electrophoresis (2-de) are key technologies in such studies. however, the many steps involved can be technically complex, and the resulting data are subject to variability from both technical and biological sources. designing 2-de proteomic studies can be challenging, as a set of standard methods or experimental designs has not been established. t ... | 2011 | 21514475 |
| nitrogen metabolism and kinetics of ammonia-oxidizing archaea. | the discovery of ammonia-oxidizing mesophilic and thermophilic group i archaea changed the century-old paradigm that aerobic ammonia oxidation is solely mediated by two small clades of beta- and gammaproteobacteria. group i archaea are extremely diverse and ubiquitous in marine and terrestrial environments, accounting for 20-30% of the microbial plankton in the global oceans. recent studies indicated that many of these organisms carry putative ammonia monooxygenase genes and are more abundant th ... | 2011 | 21514476 |
| geobacter sulfurreducens cytochrome c peroxidases: electrochemical classification of catalytic mechanisms. | bacterial cytochrome c peroxidase (ccp) enzymes are diheme redox proteins that reduce hydrogen peroxide to water. they are canonically characterized by a peroxidatic (called l, for "low reduction potential") active site heme and a secondary heme (h, for "high reduction potential") associated with electron transfer, and an enzymatic activity that exists only when the h-heme is prereduced to the fe(ii) oxidation state. the prereduction step results in a conformational change at the active site its ... | 2011 | 21524102 |
| cell-mediated deposition of porous silica on bacterial biofilms. | living hybrid materials that respond dynamically to their surrounding environment have important applications in bioreactors. silica based sol-gels represent appealing matrix materials as they form a mesoporous biocompatible glass lattice that allows for nutrient diffusion while firmly encapsulating living cells. despite progress in sol-gel cellular encapsulation technologies, current techniques typically form bulk materials and are unable to generate regular silica membranes over complex geomet ... | 2011 | 21538338 |
| effect of salinity on hydroxylamine oxidation in a marine ammonia-oxidizing gammaproteobacterium, nitrosococcus oceani strain ns58: molecular and catalytic properties of tetraheme cytochrome c-554. | tetraheme cytochrome c-554 is a physiological electron acceptor of hydroxylamine oxidoreductase (hao), a core enzyme of ammonia oxidation in chemoautotrophic nitrifiers. here we report the purification of cytochrome c-554 from nitrosococcus oceani strain ns58, a marine gammaproteobacterial ammonia-oxidizing bacterium. the ns58 cytochrome is a 25 kda-protein having four hemes c. the absorption spectrum of the cytochrome showed peaks at 420 nm, 523 nm, and 554 nm, with shoulders at around 430 nm a ... | 2010 | 21576859 |
| characteristics of the microbial community associated with ammonia oxidation in a full-scale rockwool biofilter treating malodors from livestock manure composting. | the relationship between the activity and community structure of microbes associated with the oxidation of ammonia in a full-scale rockwool biofilter was examined by kinetic, denaturing gradient gel electrophoresis (dgge), and sequence analyses. the packing materials were sampled from two different depths at 3 sites. estimated k(m) values were similar among depths at same sampling sites, while v(max) differed in the mid-point sample. the lower depth of this site had the highest v(max). a corresp ... | 2010 | 21576861 |
| microbial population dynamics and community structure during the formation of nitrifying granules to treat ammonia-rich inorganic wastewater. | microbial population dynamics were investigated during the formation of nitrifying granules in an aerobic upflow fluidized bed (aufb) reactor fed ammonia as a sole energy source. analyses of clone libraries of 16s rrna gene and the ammonia monooxygenase subunit a gene (amoa) revealed that although the clones obtained from the seed sludge were widely distributed among the ammonia-oxidizing bacteria (aob) isolates, the community structure of aob shifted towards the nitrosomonas mobilis lineage as ... | 2010 | 21576869 |
| metaproteome analysis of sewage sludge from membrane bioreactors. | microbial dynamics and enzymatic activities of activated sludge processes are not completely understood yet. a better understanding about the biology is indispensable for further process optimization. since proteins play a key role as catalysts in sludge processes, a protocol for protein extraction and analysis by 2-d page was established. it is based on phenol extraction of alkaline extracts and on a subsequent precipitation with ammonium sulphate. 2-d protein patterns obtained from different s ... | 2011 | 21604373 |
| nitrifying granules cultivation in a sequencing batch reactor at a low organics-to-total nitrogen ratio in wastewater. | it is possible to cultivate aerobic granular sludge at a low organic loading rate and organics-to-total nitrogen (cod/n) ratio in wastewater in the reactor with typical geometry (height/diameter = 2.1, superficial air velocity = 6 mm/s). the noted nitrification efficiency was very high (99%). at the highest applied ammonia load (0.3 ± 0.002 mg nh (4) (+) -n g total suspended solids (tss)(-1) day(-1), cod/n = 1), the dominating oxidized form of nitrogen was nitrite. despite a constant aeration in ... | 2011 | 21618047 |
| ammonia-oxidizing bacteria dominates over ammonia-oxidizing archaea in a saline nitrification reactor under low do and high nitrogen loading. | a continuous nitrification reactor treating saline wastewater was operated for almost one year under low dissolved oxygen (do) levels (0.15 to 0.5 mg/l) and high nitrogen loadings (0.26-0.52 kg-n/(m(3) d)) in four phases. the diversity and abundance of ammonia-oxidizing archaea (aoa) and ammonia-oxidizing bacteria (aob) were analyzed by cloning, terminal restriction fragment length polymorphism (t-rflp) and quantitative polymerase chain reaction (qpcr). the results showed that there were only on ... | 2011 | 21618465 |
| process optimization by decoupled control of key microbial populations: distribution of activity and abundance of polyphosphate-accumulating organisms and nitrifying populations in a full-scale ifas-ebpr plant. | this study investigated the abundance and distribution of key functional microbial populations and their activities in a full-scale integrated fixed film activated sludge-enhanced biological phosphorus removal (ifas-ebpr) process. polyphosphate accumulating organisms (paos) including accumulibacter and ebpr activities were predominately associated with the mixed liquor (>90%) whereas nitrifying populations and nitrification activity resided mostly (>70%) on the carrier media. ammonia oxidizer ba ... | 2011 | 21641011 |
| comparison of conventional and integrated fixed-film activated sludge systems: attached- and suspended-growth functions and quantitative polymerase chain reaction measurements. | pilot-scale integrated fixed-film activated sludge (ifas) and non-ifas control systems were compared, with respect to overall performance and functional behaviors and microbial population composition in the attached and suspended phases. the suspended phases of the control and ifas systems exhibited similar rates of ammonia consumption; the attached phase in the second aerobic ifas reactor had significantly higher rates of ammonia consumption and nitrate production than any other biomass source, ... | 2011 | 21790081 |
| influence of liberated silver from silver nanoparticles on nitrification inhibition of nitrosomonas europaea. | the ecotoxicity of silver nanoparticles (ag-nps) to wastewater biota, including ammonia oxidizing bacteria (aob), is gaining increasing interest as the number of products containing ag-nps continues to rise exponentially and they are expected to accumulate in wastewater treatment plants. this research demonstrated that the addition order of ag-np and the media constituents had a profound influence on the stability of the ag-np suspension and the corresponding repeatability of results and sensiti ... | 2011 | 21757219 |
| cold temperature decreases bacterial species richness in nitrogen-removing bioreactors treating inorganic mine waters. | explosives used in mining, such as ammonium nitrate fuel oil (anfo), can cause eutrophication of the surrounding environment by leakage of ammonium and nitrate from undetonated material that is not properly treated. cold temperatures in mines affect nitrogen removal from water when such nutrients are treated with bioreactors in situ. in this study we identified bacteria in the bioreactors and studied the effect of temperature on the bacterial community. the bioreactors consisted of sequential ni ... | 2011 | 21769859 |
| nitrification potential and population dynamics of nitrifying bacterial biofilms in response to controlled shifts of ammonium concentrations in wastewater trickling filters. | nitrogen removal in wastewater treatment is energy consuming and often carried out in biofilm nitrifying trickling filters (ntfs). we investigated nitrification potential and population dynamics of nitrifying bacteria in pilot-plant ntfs fed with full-scale plant wastewater with high (8-9mg nh(4)(+)l(-1)) or low (<0.5mg nh(4)(+)l(-1)) ammonium concentrations. after ammonium shifts, nitrification potentials stabilized after 10-43days depending on feed regime. an ntf fed with 3days of high, and 4d ... | 2011 | 21703852 |
| ammonia-oxidizing archaea and ammonia-oxidizing bacteria in six full-scale wastewater treatment bioreactors. | in this study, dideoxy sequencing and 454 high-throughput sequencing were used to analyze diversities of the ammonia monooxygenase (amoa) genes and the 16s rrna genes of ammonia-oxidizing archaea (aoa) and ammonia-oxidizing bacteria (aob) in six municipal wastewater treatment plants. the results showed that aob amoa genes were quite diverse in different wastewater treatment plants while the 16s rrna genes were relatively conserved. based on the observed complexity of amoa and 16s rrna genes, mos ... | 2011 | 21706171 |
| a specific inorganic triphosphatase from nitrosomonas europaea: structure and catalytic mechanism. | the cyth superfamily of proteins is named after its two founding members, the cyab adenylyl cyclase from aeromonas hydrophila and the human 25-kda thiamine triphosphatase. because these proteins often form a closed +¦-barrel, they are also referred to as "triphosphate tunnel metalloenzymes" (ttm). functionally, they are characterized by their ability to bind triphosphorylated substrates and divalent metal ions. these proteins exist in most organisms and catalyze different reactions, depending on ... | 2011 | 21840996 |
| analysis of the bacterial community in a laboratory-scale nitrification reactor and a wastewater treatment plant by 454-pyrosequencing. | for full understanding of the microbial community in the wastewater treatment bioreactors, one of the feasible and effective ways is to investigate the massive genetic information contained in the activated sludge. in this study, high-throughput pyrosequencing was applied to analyze the 16s rrna gene of bacteria in a laboratory-scale nitrification reactor and a full-scale wastewater treatment plant. in total, 27,458 and 26,906 effective sequence reads of the 16s rrna gene were obtained from the ... | 2011 | 21705039 |
| elemental profiling of single bacterial cells as a function of copper exposure and growth phase. | the elemental composition of single cells of nitrosomonas europaea 19718 was studied via synchrotron x-ray fluorescence microscopy (xfm) as a function of inhibition by divalent copper (cu(ii)) and batch growth phase. based on xfm, the intracellular cu concentrations in exponential phase cultures of n. europaea exposed to cu(ii) were statistically higher than in stationary phase cultures at the 95% confidence interval (+¦ôçè=ôçè0.05). however, the impact of cu inferred from specific oxygen uptake ... | 2011 | 21698126 |
| analysis of ammonia-oxidizing bacteria dominating in lab-scale bioreactors with high ammonium bicarbonate loading. | the ammonia-oxidizing bacterial community (aob) was investigated in two types of laboratory-scale bioreactors performing partial oxidation of ammonia to nitrite or nitrate at high (80-ámm) to extremely high (428-ámm) concentrations of ammonium bicarbonate. at all conditions, the dominant aob was affiliated to the nitrosomonas europaea lineage as was determined by fluorescence in situ hybridization and polymerase chain reaction in combination with denaturing gradient gel electrophoresis. molecula ... | 2011 | 21691786 |
| Biofilm formation and microbial community analysis of the simulated river bioreactor for contaminated source water remediation. | BACKGROUND, AIM, AND SCOPE: The start-up pattern of biofilm remediation system affects the biofilm characteristics and operating performances. The objective of this study was to evaluate the performances of the contaminated source water remediation systems with different start-up patterns in view of the pollutants removal performances and microbial community succession. METHODS: The operating performances of four ... | 2011 | 22120124 |