Effects of sulfide on mixotrophic denitrification by Thauera-dominated denitrifying sludge

2020 ◽  
Vol 6 (4) ◽  
pp. 1186-1195 ◽  
Author(s):  
Zhensheng Liang ◽  
Jianliang Sun ◽  
Chungeng Zhan ◽  
Siting Wu ◽  
Liang Zhang ◽  
...  
Keyword(s):  
Electron Donor ◽  
Nitrate Reduction ◽  
Nitrite Accumulation

Cultivation of Thauera-dominated denitrifying sludge can improve nitrate reduction with sulfide impacts, but nitrite accumulation should be considered when using sulfide as a complementary electron donor to treat wastewater with a low C/N ratio.

scholarly journals Uniform and Pitting Corrosion of Carbon Steel byShewanella oneidensisMR-1 under Nitrate-Reducing Conditions

2018 ◽  
Vol 84 (12) ◽  
pp. e00790-18 ◽  
Author(s):  
Robert B. Miller ◽  
Kenton Lawson ◽  
Anwar Sadek ◽  
Chelsea N. Monty ◽  
John M. Senko
Keyword(s):  
Electron Transfer ◽  
Carbon Steel ◽  
Electron Donor ◽  
Pitting Corrosion ◽  
Nitrate Reduction ◽  
Steel Corrosion ◽  
Nitrite Accumulation ◽  
Content Type ◽  
Microbially Influenced Corrosion ◽  
Reducing Conditions

ABSTRACTDespite observations of steel corrosion in nitrate-reducing environments, processes of nitrate-dependent microbially influenced corrosion (MIC) remain poorly understood and difficult to identify. We evaluated carbon steel corrosion byShewanella oneidensisMR-1 under nitrate-reducing conditions using a split-chamber/zero-resistance ammetry (ZRA) technique. This approach entails the deployment of two metal (carbon steel 1018 in this case) electrodes into separate chambers of an electrochemical split-chamber unit, where the microbiology or chemistry of the chambers can be manipulated. This approach mimics the conditions of heterogeneous metal coverage that can lead to uniform and pitting corrosion. The current between working electrode 1 (WE1) and WE2 can be used to determine rates, mechanisms, and, we now show, extents of corrosion. WhenS. oneidensiswas incubated in the WE1 chamber with lactate under nitrate-reducing conditions, nitrite transiently accumulated, and electron transfer from WE2 to WE1 occurred as long as nitrite was present. Nitrite in the WE1 chamber (withoutS. oneidensis) induced electron transfer in the same direction, indicating that nitrite cathodically protected WE1 and accelerated the corrosion of WE2. WhenS. oneidensiswas incubated in the WE1 chamber without an electron donor, nitrate reduction proceeded, and electron transfer from WE2 to WE1 also occurred, indicating that the microorganism could use the carbon steel electrode as an electron donor for nitrate reduction. Our results indicate that under nitrate-reducing conditions, uniform and pitting carbon steel corrosion can occur due to nitrite accumulation and the use of steel-Fe(0) as an electron donor, but conditions of sustained nitrite accumulation can lead to more-aggressive corrosive conditions.IMPORTANCEMicrobially influenced corrosion (MIC) causes damage to metals and metal alloys that is estimated to cost over $100 million/year in the United States for prevention, mitigation, and repair. While MIC occurs in a variety of settings and by a variety of organisms, the mechanisms by which microorganisms cause this damage remain unclear. Steel pipe and equipment may be exposed to nitrate, especially in oil and gas production, where this compound is used for corrosion and “souring” control. In this paper, we show uniform and pitting MIC under nitrate-reducing conditions and that a major mechanism by which it occurs is via the heterogeneous cathodic protection of metal surfaces by nitrite as well as by the microbial oxidation of steel-Fe(0).

scholarly journals Simultaneous nitrate and organic matter removal from a dairy effluent by biodenitrification

2018 ◽  
Vol 31 (2) ◽  
pp. 97-107
Author(s):  
Ahmed Hamdani ◽  
Mohammed Mountadar ◽  
Omar Assobhei
Keyword(s):  
Organic Matter ◽  
Chemical Oxygen Demand ◽  
Electron Donor ◽  
High Efficiency ◽  
Oxygen Demand ◽  
Nitrite Accumulation ◽  
Simultaneous Removal ◽  
Optimal Conditions ◽  
Dairy Effluent ◽  
Organic Removal

In order to study the simultaneous removal of nitrate and organic matter from a dairy effluent containing 670 mg∙L-1 of nitrate (NO3--N) and 5 760 mg∙L-1 of dissolved chemical oxygen demand (CODd), denitrification in a laboratory scale bioreactor consisting of an immersed bacterial bed colonized by an heterotrophic denitrifying flora (HDF) selected for NO3- reduction, COD consumption and adapted to grow on an effluent produced by a dairy industry was investigated. The obtained results indicated that at the optimal conditions of temperature (30°C), pH (7), COD/NO3--N ratio (5), the operation lasted 108h with total reduction of nitrate in 72h, no nitrite accumulation, and 92% of soluble COD removal in 96h. This indicates that the biodenitrification was accompanied with a high efficiency of matter organic removal as an electron donor, and thereby satisfies the applicable standards.

Enhanced microbial nitrate reduction using natural manganese oxide ore as an electron donor

2022 ◽  
Vol 306 ◽  
pp. 114497
Author(s):  
Zhixing Xiao ◽  
Qitao Jiang ◽  
Yi Li ◽  
Jun Zhou ◽  
Dan Chen ◽  
...  
Keyword(s):  
Manganese Oxide ◽  
Electron Donor ◽  
Nitrate Reduction ◽  
Manganese Oxide Ore

scholarly journals Groundwater cable bacteria conserve energy by sulfur disproportionation

2019 ◽  
Vol 14 (2) ◽  
pp. 623-634 ◽  
Author(s):  
Hubert Müller ◽  
Sviatlana Marozava ◽  
Alexander J. Probst ◽  
Rainer U. Meckenstock
Keyword(s):  
16S Rrna ◽  
Electron Donor ◽  
Nitrate Reduction ◽  
Elemental Sulfur ◽  
Single Cells ◽  
Sulfur Oxidation ◽  
Metabolic Reconstruction ◽  
Rrna Gene ◽  
Long Distance ◽  
Sulfur Disproportionation

AbstractCable bacteria of the family Desulfobulbaceae couple spatially separated sulfur oxidation and oxygen or nitrate reduction by long-distance electron transfer, which can constitute the dominant sulfur oxidation process in shallow sediments. However, it remains unknown how cells in the anoxic part of the centimeter-long filaments conserve energy. We found 16S rRNA gene sequences similar to groundwater cable bacteria in a 1-methylnaphthalene-degrading culture (1MN). Cultivation with elemental sulfur and thiosulfate with ferrihydrite or nitrate as electron acceptors resulted in a first cable bacteria enrichment culture dominated >90% by 16S rRNA sequences belonging to the Desulfobulbaceae. Desulfobulbaceae-specific fluorescence in situ hybridization (FISH) unveiled single cells and filaments of up to several hundred micrometers length to belong to the same species. The Desulfobulbaceae filaments also showed the distinctive cable bacteria morphology with their continuous ridge pattern as revealed by atomic force microscopy. The cable bacteria grew with nitrate as electron acceptor and elemental sulfur and thiosulfate as electron donor, but also by sulfur disproportionation when Fe(Cl)2 or Fe(OH)3 were present as sulfide scavengers. Metabolic reconstruction based on the first nearly complete genome of groundwater cable bacteria revealed the potential for sulfur disproportionation and a chemo-litho-autotrophic metabolism. The presence of different types of hydrogenases in the genome suggests that they can utilize hydrogen as alternative electron donor. Our results imply that cable bacteria not only use sulfide oxidation coupled to oxygen or nitrate reduction by LDET for energy conservation, but sulfur disproportionation might constitute the energy metabolism for cells in large parts of the cable bacterial filaments.

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.

Wood derived biochar as electron donor and its influence on microbial denitrification: Role of extracellular polymeric substances in extracellular electron transfer

2020 ◽  
Author(s):  
Kuppusamy Sathishkumar ◽  
Yi Li ◽  
Rana Muhammad Adnan Ikram
Keyword(s):  
Electron Transfer ◽  
Electron Donor ◽  
Electrochemical Behavior ◽  
Nitrate Reduction ◽  
Extracellular Polymeric Substances ◽  
Electrochemical Impedance ◽  
Electrochemical Analysis ◽  
Extracellular Electron Transfer ◽  
Microbial Denitrification

<p>Biochar is extensively used in environmental pollutant remediation because of its diverse property, however the effect of biochar on microbial nitrate reduction and electrochemical behavior of biochar remain unknown. Also electron transfer from the microbial cells to electron donor or acceptor have been transport across the extracellular polymeric substances (EPS), however it was unclear whether extracellular polymeric substances captured or enhance the electrons.  Hence, aim of the present study is to investigate the electrochemical behavior of biochar and its effects on microbial nitrate reduction and elucidate the role of extracellular polymeric substances in extracellular electron transfer (EET).  The biochar was prepared at different pyrolysis temperatures (400 °C, 500 °C and 600 °C) and their electrochemical behavior was characterized by electrochemical analysis (cyclic voltammetry, electrochemical impedance spectrum, chronoamperometry). Results demonstrated that all the biochars could donate and accept the electrons, impact of biochar on microbial nitrate reduction was studied and the results showed that biochar prepared at 400 °C significantly enhances microbial nitrate reduction process. Phenol O-H and quinone C=O surface functional groups on the biochar contributes in the overall electron exchange which accelerated the nitrate reduction. The role of EPS in EET by electrochemical analysis results reveals that outer membrane c-type cytochrome and flavin protein from the biofilm was involved in electron transfer process, and EPS act as transient media for microbial EET. Overall, present study suggested that biochar could be used as eco-friendly material for the enhancement of microbial denitrification.</p>

scholarly journals Regulation of nap Gene Expression and Periplasmic Nitrate Reductase Activity in the Phototrophic Bacterium Rhodobacter sphaeroides DSM158

2002 ◽  
Vol 184 (6) ◽  
pp. 1693-1702 ◽  
Author(s):  
Mónica Gavira ◽  
M. Dolores Roldán ◽  
Francisco Castillo ◽  
Conrado Moreno-Vivián
Keyword(s):  
Rhodobacter Sphaeroides ◽  
Nitrate Reduction ◽  
Reductase Activity ◽  
Enzyme Activation ◽  
Nitrite Accumulation ◽  
Northern Blots ◽  
Reverse Transcription Pcr ◽  
Phototrophic Growth ◽  
Very High

ABSTRACT Bacterial periplasmic nitrate reductases (Nap) can play different physiological roles and are expressed under different conditions depending on the organism. Rhodobacter sphaeroides DSM158 has a Nap system, encoded by the napKEFDABC gene cluster, but nitrite formed is not further reduced because this strain lacks nitrite reductase. Nap activity increases in the presence of nitrate and oxygen but is unaffected by ammonium. Reverse transcription-PCR and Northern blots demonstrated that the napKEFDABC genes constitute an operon transcribed as a single 5.5-kb product. Northern blots and nap-lacZ fusions revealed that nap expression is threefold higher under aerobic conditions but is regulated by neither nitrate nor ammonium, although it is weakly induced by nitrite. On the other hand, nitrate but not nitrite causes a rapid enzyme activation, explaining the higher Nap activity found in nitrate-grown cells. Translational nap′-′lacZ fusions reveal that the napK and napD genes are not efficiently translated, probably due to mRNA secondary structures occluding the translation initiation sites of these genes. Neither butyrate nor caproate increases nap expression, although cells growing phototrophically on these reduced substrates show a very high Nap activity in vivo (nitrite accumulation is sevenfold higher than in medium with malate). Phototrophic growth on butyrate or caproate medium is severely reduced in the NapA− mutants. Taken together, these results indicate that nitrate reduction in R. sphaeroides is mainly regulated at the level of enzyme activity by both nitrate and electron supply and confirm that the Nap system is involved in redox balancing using nitrate as an ancillary oxidant to dissipate excess reductant.

scholarly journals Complete bromate and nitrate reduction using hydrogen as the sole electron donor in a rotating biofilm-electrode reactor

2016 ◽  
Vol 307 ◽  
pp. 82-90 ◽  
Author(s):  
Yu Zhong ◽  
Xin Li ◽  
Qi Yang ◽  
Dongbo Wang ◽  
Fubing Yao ◽  
...  
Keyword(s):  
Electron Donor ◽  
Nitrate Reduction

scholarly journals Impact of Different In Vitro Electron Donor/Acceptor Conditions on Potential Chemolithoautotrophic Communities from Marine Pelagic Redoxclines

2005 ◽  
Vol 71 (11) ◽  
pp. 6664-6672 ◽  
Author(s):  
Matthias Labrenz ◽  
Günter Jost ◽  
Christa Pohl ◽  
Sabrina Beckmann ◽  
Willm Martens-Habbena ◽  
...  
Keyword(s):  
Electron Donor ◽  
Nitrate Reduction ◽  
Single Strand Conformation Polymorphism ◽  
General Importance ◽  
Donor Acceptor ◽  
Dark Fixation ◽  
Enrichment Experiments ◽  
Chemolithoautotrophic Bacteria ◽  
The Impact

ABSTRACT Anaerobic or microaerophilic chemolithoautotrophic bacteria have been considered to be responsible for CO2 dark fixation in different pelagic redoxclines worldwide, but their involvement in redox processes is still not fully resolved. We investigated the impact of 17 different electron donor/acceptor combinations in water of pelagic redoxclines from the central Baltic Sea on the stimulation of bacterial CO2 dark fixation as well as on the development of chemolithoautotrophic populations. In situ, the highest CO2 dark fixation rates, ranging from 0.7 to 1.4 μmol liter−1 day−1, were measured directly below the redoxcline. In enrichment experiments, chemolithoautotrophic CO2 dark fixation was maximally stimulated by the addition of thiosulfate, reaching values of up to 9.7 μmol liter−1 CO2 day−1. Chemolithoautotrophic nitrate reduction proved to be an important process, with rates of up to 33.5 μmol liter−1 NO3 − day−1. Reduction of Fe(III) or Mn(IV) was not detected; nevertheless, the presence of these potential electron acceptors influenced the development of stimulated microbial assemblages. Potential chemolithoautotrophic bacteria in the enrichment experiments were displayed on 16S ribosomal complementary DNA single-strand-conformation polymorphism fingerprints and identified by sequencing of excised bands. Sequences were closely related to chemolithoautotrophic Thiomicrospira psychrophila and Maorithyas hadalis gill symbiont (both Gammaproteobacteria) and to an uncultured nitrate-reducing Helicobacteraceae bacterium (Epsilonproteobacteria). Our data indicate that this Helicobacteraceae bacterium could be of general importance or even a key organism for autotrophic nitrate reduction in pelagic redoxclines.

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