Characteristics of Nitrate Reduction Using Fe (II) as Electron Donor in Activated Sludge

2016 ◽  
Vol 33 (6) ◽  
pp. 505-512 ◽  
Author(s):  
Hongyu Wang ◽  
Yaping Ye ◽  
Jinni Sai ◽  
Dan Chen ◽  
Kai Yang ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Electron Donor ◽  
Nitrate Reduction

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.

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 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

Simultaneous biological removal of sulphide and nitrate by autotrophic denitrification in an activated sludge system

2006 ◽  
Vol 53 (12) ◽  
pp. 91-99 ◽  
Author(s):  
I. Manconi ◽  
A. Carucci ◽  
P. Lens ◽  
S. Rossetti
Keyword(s):  
Activated Sludge ◽  
Removal Efficiency ◽  
Electron Donor ◽  
Product Formation ◽  
Fish Analysis ◽  
Autotrophic Denitrification ◽  
Biological Removal ◽  
N Removal ◽  
Activated Sludge Reactor ◽  
Denitrification Process

The feasibility of an autotrophic denitrification process in an activated sludge reactor, using sulphide as the electron donor, was tested for simultaneous denitrification and sulphide removal. The reactor was operated at nitrate (N) to sulphide (S) ratios between 0.5 and 0.9 to evaluate their effect on theN-removal efficiency, the S-removal efficiency and the product formation during anoxic oxidation of sulphide. One hundred per cent removal of both nitrate and sulphide was achieved at a NLR of 7.96 mmol N·L−1·d−1 (111.44 mg NO3−-N·L−1·d−1) and at a N/S ratio of 0.89 with complete oxidation of sulphide to sulphate. The oxygen level in the reactor (10%) was found to influence the N-removal efficiency by inhibiting the denitrification process. Moreover, chemical (or biological) oxidation of sulphide with oxygen occurred, resulting in a loss of the electron donor. FISH analysis was carried out to study the microbial population in the system.

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.

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.

Organic and nitrogen removal with minimal COD requirement by integration of sequestered denitrification and separate nitrification in a low-loaded activated sludge process

2000 ◽  
Vol 42 (12) ◽  
pp. 65-72 ◽  
Author(s):  
H.-S. Shin ◽  
S.-Y. Nam
Keyword(s):  
Organic Matter ◽  
Activated Sludge ◽  
Electron Donor ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Contact Process ◽  
Oxygen Demand ◽  
Specific Mass ◽  
Film Reactor ◽  
Soluble Chemical Oxygen Demand

A separate sludge system incorporating sequencing batch reactor (SBR) for sequestered denitrification and an immobilized fixed-film reactor for nitrification was investigated in this study. Emphases were placed on the preservation of organic matter as an electron donor for denitrification and the improvement of nitrification efficiency by using an immobilization technique with alginate coating. To preserve organic materials in the sludge required for denitrification, a study was made with a contact process. The contactor, when operated with a short detention time, gave incomplete metabolism of organic matter. With 64% of the influent soluble chemical oxygen demand (SCOD) was adsorbed to activated sludge within 30 min. The specific mass of organic matter uptaken was 55 mg SCOD/g mixed liquor suspended solids (MLSS), which enhanced the denitrification efficiency up to 63% in the following denitrification step. Thus, the required COD in the proposed system can be saved up to 63% as an available electron donor for the conventional aerobic process. The immobilized nitrification unit showed over 90% of nitrate production rate up to 50 mg/l of influent ammonia load.

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