scholarly journals Biogenic Fe(II-III) Hydroxycarbonate Green Rust Enhances Nitrate Removal and Decreases Ammonium Selectivity during Heterotrophic Denitrification

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 818
Author(s):  
Georges Ona-Nguema ◽  
Delphine Guerbois ◽  
Céline Pallud ◽  
Jessica Brest ◽  
Mustapha Abdelmoula ◽  
...  
Keyword(s):  
Nitrate Reduction ◽  
Nitrate Removal ◽  
Green Rust ◽  
Nitrite Reduction ◽  
Nitrite Accumulation ◽  
Bacterial Reduction ◽  
Water Treatment Process ◽  
Nitrite Production ◽  
Ammonium Production ◽  
Biogenic Iron

Nitrification-denitrification is the most widely used nitrogen removal process in wastewater treatment. However, this process can lead to undesirable nitrite accumulation and subsequent ammonium production. Biogenic Fe(II-III) hydroxycarbonate green rust has recently emerged as a candidate to reduce nitrite without ammonium production under abiotic conditions. The present study investigated whether biogenic iron(II-III) hydroxycarbonate green rust could also reduce nitrite to gaseous nitrogen during bacterial nitrate reduction. Our results showed that biogenic iron(II-III) hydroxycarbonate green rust could efficiently decrease the selectivity of the reaction towards ammonium during heterotrophic nitrate reduction by native wastewater-denitrifying bacteria and by three different species of Shewanella: S. putrefaciens ATCC 12099, S. putrefaciens ATCC 8071 and S. oneidensis MR-1. Indeed, in the absence of biogenic hydroxycarbonate green rust, bacterial reduction of nitrate converted 11–42% of the initial nitrate into ammonium, but this value dropped to 1–28% in the presence of biogenic hydroxycarbonate green rust. Additionally, nitrite accumulation did not exceed the 2–13% in the presence of biogenic hydroxycarbonate green rust, versus 0–28% in its absence. Based on those results that enhance the extent of denitrification of about 60%, the study proposes a water treatment process that couples the bacterial nitrite production with the abiotic nitrite reduction by biogenic green rust.

Nitrate reduction and nitrogenase activity in Spirillum lipoferum

1977 ◽  
Vol 23 (3) ◽  
pp. 306-310 ◽  
Author(s):  
Carlos A. Neyra ◽  
Peter Van Berkum
Keyword(s):  
Nitrate Reduction ◽  
Time Course ◽  
Nitrogenase Activity ◽  
Reductase Activity ◽  
Nitrite Reduction ◽  
Lag Phase ◽  
Nitrite Accumulation ◽  
Assimilatory Nitrate Reduction ◽  
Nitrate And Nitrite ◽  
Anaerobic Pretreatment

Nitrate and nitrite reduction under aerobic, microaerophillic, and anaerobic conditions was demonstrated in Spirillum lipoferum (ATCC 29145). Nitrite did not accumulate during assimilatory nitrate reduction in air. The nitrite produced during dissimilatory nitrate reduction accumulated in the medium but not in the cells. On exposure of the bacteria to nitrate and anaerobiosis, a low initial rate (lag) was followed by accelerated rates of nitrite accumulation. A 3-h anaerobic pretreatment, in the absence of nitrate, did not avoid the lag phase. No nitrate reductase activity (NRA) developed in the presence of chloramphenicol. The data suggest that induction of anaerobic NRA in S. lipoferum required nitrate and protein synthesis.Anaerobic N2ase activity by S. lipoferum was greatly stimulated in the presence of nitrate. The time course of nitrate reduction was coincidental with the pattern of nitrate-stimulated N2ase activity indicating that a relationship exists between these two processes.

scholarly journals Glycerol-driven Denitratation: Process Kinetics, Microbial Ecology, and Operational Controls

2021 ◽  
Author(s):  
Matthew P. Baideme ◽  
Chenghua Long ◽  
Luke T. Plante ◽  
Jeffrey A. Starke ◽  
Michael A. Butkus ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Microbial Ecology ◽  
Nitrate Reduction ◽  
Carbon Sources ◽  
Selective Reduction ◽  
Nitrite Reduction ◽  
Nitrite Accumulation ◽  
Ammonium Oxidation ◽  
Order Of Magnitude ◽  
Nitrate And Nitrite

ABSTRACTDenitratation, the selective reduction of nitrate to nitrite, is a novel process when coupled with anaerobic ammonium oxidation (anammox) could achieve resource-efficient biological nitrogen removal of ammonium- and nitrate-laden waste streams. Using a fundamentally-based, first principles approach, this study optimized a stoichiometrically-limited, glycerol-driven denitratation process and characterized mechanisms supporting nitrite accumulation with results that aligned with expectations. Glycerol supported selective nitrate reduction to nitrite and near-complete nitrate conversion, indicating its viability in a denitratation system. Glycerol-supported specific rates of nitrate reduction (135.3 mg-N/g-VSS/h) were at least one order of magnitude greater than specific rates of nitrite reduction (14.9 mg-N/g-VSS/h), potentially resulting in transient nitrite accumulation and indicating glycerol’s superiority over other organic carbon sources in denitratation systems. pH and ORP inflection points in nitrogen transformation assays corresponded to maximum nitrite accumulation, indicating operational setpoints to prevent further nitrite reduction. Denitratation conditions supported enrichment of Thauera sp. as the dominant genus. Stoichiometric limitation of influent organic carbon, coupled with differential nitrate and nitrite reduction kinetics, optimized operational controls, and a distinctively enriched microbial ecology, was identified as causal in glycerol-driven denitratation.

Cellular regulation of nitrate uptake in denitrifying Flexibacter canadensis

1994 ◽  
Vol 40 (7) ◽  
pp. 576-582 ◽  
Author(s):  
Qitu Wu ◽  
Roger Knowles
Keyword(s):  
Nitrate Reductase ◽  
Nitrate Uptake ◽  
Inhibitory Effect ◽  
Nitrite Reduction ◽  
Nitrite Accumulation ◽  
Cellular Regulation ◽  
Oxygen Inhibition ◽  
Whole Cells ◽  
Nitrite Production ◽  
Carbonyl Cyanide

Nitrate uptake and its regulation were investigated using an ion-specific nitrate electrode for denitrifying Flexibacter canadensis under anaerobic conditions. Glucose supported a greater rate of nitrate uptake than did glycerol, glutamate, lactose, cellobiose, or ethanol. Nitrate uptake closely approximated Michaelis–Menten kinetics; the estimated Ks(glucose) and apparent Km(nitrate) for nitrate uptake were 21 and 44 μM, respectively. Nitrate disappearance was correlated with nitrite accumulation, and nitrate had an inhibitory effect on nitrite reduction. Oxygen inhibition of nitrate uptake increased as the percent air saturation increased, and reversed readily as the percent air saturation decreased. The minimal air saturation showing inhibition of nitrate uptake was about 2–4%. Azide and cyanide completely inhibited nitrate uptake. No nitrate uptake was observed in cells grown in the presence of 1 or 5 mM tungstate (no added molybdate). When molybdate (100–200μM) was present in the medium, nitrate uptake was exhibited by organisms grown with 1 mM, but not with 5 mM, tungstate, indicating that nitrate uptake was dependent on the presence of an active nitrate reductase, and that competition between tungsten and molybdenum occurred during the formation of nitrate reductase. Nitrite production from nitrate by whole cells but not cell-free extracts was inhibited by 2,4-dinitrophenol and carbonyl cyanide m-chlorophenylhydrazone, indicating that nitrate and (or) nitrite transport depended upon the electrochemical proton gradient.Key words: denitrification, nitrate uptake, Flexibacter canadensis.

scholarly journals Light-Mediated Nitrite Accumulation during Denitrification by Pseudomonas sp. Strain JR12

1998 ◽  
Vol 64 (3) ◽  
pp. 813-817 ◽  
Author(s):  
Yoram Barak ◽  
Yossi Tal ◽  
Jaap van Rijn
Keyword(s):  
Nitrate Reduction ◽  
Electron Flow ◽  
Inhibitory Effect ◽  
Nitrite Reduction ◽  
Aerobic Respiration ◽  
Nitrite Accumulation ◽  
Respiratory Pathway ◽  
Low Light ◽  
Light Inhibition ◽  
Effect Of Light

ABSTRACT The effect of light on the denitrifying characteristics of a nonphotosynthetic denitrifier, Pseudomonas sp. strain JR12, was examined. Already at low light intensities, nitrite accumulated as a result of light inhibition of nitrite but not of nitrate reduction rates. Exposure of this bacterium to light caused a photooxidation of cytochrome c, an intermediate electron carrier in its respiratory pathway. Photoinhibition of nitrite reduction was reversible, as nitrite reduction rates returned to preillumination levels when light-exposed cells were returned to dark conditions. Antimycin A reversed the inhibitory effect of light on nitrite reduction by preventing a reversed electron flow. Aerobic respiration by this bacterium was not affected by light.

Effect of Herbicides on In Vivo Nitrate and Nitrite Reduction

Weed Science ◽  
1977 ◽  
Vol 25 (1) ◽  
pp. 18-22 ◽  
Author(s):  
R.L. Finke ◽  
R.L. Warner ◽  
T.J. Muzik
Keyword(s):  
Hordeum Vulgare ◽  
Nitrate Reductase ◽  
Nitrate Reduction ◽  
Amaranthus Retroflexus ◽  
Nitrite Reduction ◽  
Nitrite Accumulation ◽  
Inhibitory Effects ◽  
Potassium Azide ◽  
Nitrate And Nitrite

The effects of herbicides on in vivo nitrate and nitrite reduction were determined by vacuum infiltrating sections of barley (Hordeum vulgareL.) or bean (Phaseolus vulgarisL.) leaves with solutions containing nitrate and herbicides. Herbicides causing a reduction of nitrite accumulation in the dark were considered to have inhibitory effects upon nitrate reduction and those causing an accumulation of nitrite in the light were considered to inhibit nitrite reduction. Only dinoseb (2-sec-butyl-4,6-dinitrophenol) and potassium azide significantly reduced nitrate reduction in both barley and bean. All of the herbicides which inhibit photosynthesis inhibited nitrite reduction but had no significant effect on nitrate reduction in barley and bean. Nitrite reduction in an atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] resistant pigweed (Amaranthus retroflexusL.) biotype was not affected by any triazine tested. However, these triazines significantly inhibited nitrite reduction in barley, bean, and the susceptible pigweed biotype. The results suggest that the in vivo nitrate reductase technique may be a useful technique for identifying chemicals which inhibit the flow of electrons to ferredoxin, thereby inhibiting nitrite reduction in light.

scholarly journals Dissimilatory Nitrate Reduction to Ammonium in the Cable Bacterium Ca. Electronema Sp. GS

2020 ◽  
Author(s):  
Ugo Marzocchi ◽  
Casper Thorup ◽  
Ann-Sofie Dam ◽  
Andreas Schramm ◽  
Nils Risgaard-Petersen
Keyword(s):  
Nitrate Reduction ◽  
Electron Flux ◽  
Sulfide Oxidation ◽  
Nitrite Reduction ◽  
Sulphide Oxidation ◽  
Dissimilatory Nitrate Reduction ◽  
Nitrite Production ◽  
Genes Encoding ◽  
Energy Conserving ◽  
Multiheme Cytochrome

ABSTRACTCable bacteria are filamentous Desulfobulbaceae that split the energy-conserving reaction of sulphide oxidation into two half reactions occurring in distinct cells. Cable bacteria can use nitrate, but the reduction pathway is unknown, making it difficult to assess their direct impact on the N-cycle. Here we show that the freshwater cable bacterium Ca. Electronema sp. GS performs dissimilatory nitrate reduction to ammonium (DNRA). 15NO3−-amended sediment with Ca. Electronema sp. GS showed higher rates of DNRA and nitrite production than sediment without Ca. Electronema sp. GS. Electron flux from sulphide oxidation, inferred from electric potential measurements, matched the electron flux needed to drive cable bacteria-mediated nitrate reduction. Ca. Electronema sp. GS expressed a complete nap operon for periplasmic nitrate reduction to nitrite, and genes encoding a periplasmic multiheme cytochrome (pMHC), homolog to a pMHC that can catalyse nitrite reduction to ammonium in Ca. Maribeggiatoa. Phylogenetic analysis suggests that the capacity for DNRA was acquired in multiple events through horizontal gene transfer from different organisms, before cable bacteria split into different salinity niches. The architecture of the nitrate reduction system suggests absence of energy conservation through oxidative phosphorylation, indicating that cable bacteria primarily conserve energy through the half reaction of sulfide oxidation.

Structural Changes of Bimetallic PdX/Cu (1-X) Nanocatalysts Developed for Nitrate Reduction of Drinking Water

2005 ◽  
Vol 876 ◽  
Author(s):  
Huiping Xu ◽  
Ray Twesten ◽  
Kathryn Guy ◽  
John Shapley ◽  
Charles Werth ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Drinking Water ◽  
Catalytic Activity ◽  
Nitrate Reduction ◽  
Structural Changes ◽  
Nitrate Removal ◽  
High Resolution Electron Microscopy ◽  
Nitrite Reduction ◽  
Contrast Imaging ◽  
Promising Alternative

AbstractReductive removal by hydrogeneration using supported Pd/M (M= Cu, Pt, Ag, Co, Fe, Mo, Ni, Rh, Ir, Mn and Cr) bimetallic catalysts has emerged as a promising alternative for nitrate removal in drinking water [1]. Fundamental understanding how the atomic arrangement of Pd and a second element, such as Cu, affect the activity nitrite reduction and selectivity of dinitrogen will be accomplished by coordinated synthesis (Shapley), activity/selectivity/efficiency measurements (Werth) and nanostructure determination (Yang & Xu). In this paper, we report a systematic study of novel polyvinylpyrrolidone (PVP) stabilized nanoscale Pd-Cu colloids, with homogeneous and narrow size distribution, with Pd: Cu ratios varying from 50:50 to 90:10. Initial measurements on catalytic activity for nitrate reduction demonstrated a dependence on the relative composition. Electron microscopy studies, including Z-contrast imaging [2], energy-dispersive X-ray emission (EDX), electron diffraction and high-resolution electron microscopy (HREM), revealed a surprising change in structure at the 80:20 Pd-Cu composition, where, with less than 80% Pd,the nanoparticle forms a core-shell structure but for nanoparticles containing 80% or more Pd, it is homogeneous. We are at the pivotal point of directly correlating these nano-structures with the catalytic activity. Such an understanding is essential for the efficient development of catalysts for the purification of drinking water.

scholarly journals Preparation of Co/Ti electrode by electro-deposition for aqueous nitrate reduction

2021 ◽  
Author(s):  
Bicun Jiang ◽  
Liqin Han ◽  
Juntian Wang ◽  
Chang Lu ◽  
Yang Pan ◽  
...  
Keyword(s):  
Nitrate Reduction ◽  
Nitrate Removal ◽  
Ammonium Nitrogen ◽  
Nitrite Reduction ◽  
Electrolysis Cell ◽  
Ammonium Oxidation ◽  
Nitrogen Gas ◽  
Electro Deposition ◽  
Improved Stability ◽  
Chlorine Ion

Abstract A Co/Ti electrode for nitrate reduction was prepared by electrode-deposition. In the single-compartment electrolysis cell, nitrate (100 mg/L) removal reached nearly 100% after 3 h electrolysis under the current density of 20 mA cm–2 by using the Co/Ti electrode as cathode, and the main reduction products were ammonium nitrogen (66.5%) and nitrogen gas (33.5%). This performance on nitrate removal was comparable to a Co3O4/Ti electrode, and the electroactivity of the Co/Ti electrode towards nitrite reduction was higher than that of a Co3O4/Ti electrode. The Co/Ti electrode exhibited an improved stability with 18.7% of mass loss and 25.5% of Co dissolution compared with the Co3O4/Ti electrode after ultrasonic interference. The presence of chlorine ion (1,000 mg/L) could promote the total nitrogen (TN) removal to approximately 100% after 3 h electrolysis because of the ammonium oxidation by the free chlorine produced from the anode. In the presence of calcium (50 mg/L) and phosphate (0.5 mg/L), the nitrate removal decreased from 85.4 ± 1.5 to 57.7 ± 3.5% after ten reuse cycles. This result suggests that Ca and P should be pre-removed before the electro-reduction of nitrate.

scholarly journals Effects of cobalt-histidine absorbent on aerobic denitrification by Paracoccus versutus LYM

AMB Express ◽  
2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Chaoyue Sun ◽  
Yu Zhang ◽  
Zhenping Qu ◽  
Jiti Zhou
Keyword(s):  
Nitrate Reduction ◽  
Nitrite Reduction ◽  
Aerobic Denitrification ◽  
Chemical Absorption ◽  
Binding Ability ◽  
Biological Reduction ◽  
Distinct Effect ◽  
The Future

AbstractTo overcome the problem that ferrous complexes are easily oxidized by O2 and then lose NO binding ability in the chemical absorption-biological reduction (CABR) process, cobalt(II)-histidine [Co(II)His] was proposed as an alternative. To evaluate the applicability of Co(II)His, the effects of CoHis absorbent on the aerobic denitrification by Paracoccus versutus LYM were investigated. Results indicated that His significantly promoted nitrite reduction. The inhibition effects of CoHis absorbent could be substantially alleviated by increasing the initial His/Co2+ to 4 or higher. CoHis with concentrations of 4, 8, 12, 16 and 20 mM presented no distinct effect on nitrite reduction, but slightly inhibited the reduction of nitrate, resulting in longer lag of nitrate reduction, and obviously promoted the growth of strain LYM. In the presence of 5, 10, 15 and 20 mM CoHis absorbent, the main denitrification product was N2 (not less than 95.0%). This study is of significance in verifying the applicability of Co(II)His in the CABR process, and provides a referable CoHis absorbent concentration as 20 mM with an initial His/Co2+ of 4 for the future experiments.

Relation Between CO2 Evolution and in situ Reduction of Nitrate in Wheat Leaves

1981 ◽  
Vol 8 (6) ◽  
pp. 515 ◽  
Author(s):  
MS Naik ◽  
DJD Nicholas
Keyword(s):  
Citric Acid ◽  
Nitrate Reduction ◽  
Citric Acid Cycle ◽  
Nitrate Assimilation ◽  
Co2 Evolution ◽  
In Situ Reduction ◽  
Acid Cycle ◽  
Nitrite Production ◽  
Wheat Leaves

In wheat leaf discs the evolution of 14CO2 from exogenously supplied 14C-labelled citric acid cycle intermediates was stimulated during the in situ anaerobic reduction of nitrate in the dark. Under these conditions, however, [1,4-14C]succinate was not metabolized. Similarly, when leaves were allowed to assimilate 14CO2 in the dark, thus producing endogenously labelled organic acids, the subsequent evolution of 14CO2 from discs prepared from these leaves was strongly dependent on nitrate reduction. A 1 : 1 stoichiometry between nitrite production and CO2 evolution was recorded during this in situ reduction of nitrate. The in situ reduction of nitrate was inhibited by malonate and D-malate and this effect was reversed by fumarate, probably by generating L-malate within the mitochondria. Mitochondrial NAD-malic enzyme (decarboxylating) (EC 1.1.1.38) was similarly inhibited competitively by malonate and D-malate, but not by succinate. These results indicate that the citric acid cycle dehydrogenases which generate CO2 supply NADH for nitrate reduction in wheat leaves. It is likely that, under anaerobic conditions, nitrate acts as an alternative oxidant to O2 for the NADH generated by the citric acid cycle dehydrogenases resulting in simultaneous evolution of CO2. This ensures that the citric acid cycle operates at the required rate for nitrate assimilation.

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