scholarly journals Distribution of Nitrosomonas europaea andParacoccus denitrificans Immobilized in Tubular Polymeric Gel for Nitrogen Removal

2000 ◽  
Vol 66 (2) ◽  
pp. 816-819 ◽  
Author(s):  
Hiroaki Uemoto ◽  
Hiroshi Saiki
Keyword(s):  
Electron Donor ◽  
Nitrogen Removal ◽  
Oxidation Rate ◽  
Paracoccus Denitrificans ◽  
Nitrosomonas Europaea ◽  
Gaseous Hydrogen ◽  
External Region ◽  
Polymeric Gel

ABSTRACT To improve the cooperative removal of nitrogen byNitrosomonas europaea and Paracoccus denitrificans, we controlled their distribution in a tubular gel. When ethanol was supplied inside the tubular gel as an electron donor, their distributions overlapped in the external region of the gel. By changing the electron donor from ethanol to gaseous hydrogen, the distribution of P. denitrificans shifted to the inside of the tube and was separated from that of N. europaea. The separation resulted in an increase of the oxidation rate of ammonia by 25%.

scholarly journals Aerobic Denitrifying Bacteria That Produce Low Levels of Nitrous Oxide

2003 ◽  
Vol 69 (6) ◽  
pp. 3152-3157 ◽  
Author(s):  
Naoki Takaya ◽  
Maria Antonina B. Catalan-Sakairi ◽  
Yasushi Sakaguchi ◽  
Isao Kato ◽  
Zhemin Zhou ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Nitrogen Removal ◽  
Paracoccus Denitrificans ◽  
Pseudomonas Stutzeri ◽  
Denitrifying Bacteria ◽  
Continuous Cultures ◽  
Aerobic Conditions ◽  
Stage Process ◽  
Low Levels ◽  
Microbial N

ABSTRACT Most denitrifiers produce nitrous oxide (N2O) instead of dinitrogen (N2) under aerobic conditions. We isolated and characterized novel aerobic denitrifiers that produce low levels of N2O under aerobic conditions. We monitored the denitrification activities of two of the isolates, strains TR2 and K50, in batch and continuous cultures. Both strains reduced nitrate (NO3 −) to N2 at rates of 0.9 and 0.03 μmol min−1 unit of optical density at 540 nm−1 at dissolved oxygen (O2) (DO) concentrations of 39 and 38 μmol liter−1, respectively. At the same DO level, the typical denitrifier Pseudomonas stutzeri and the previously described aerobic denitrifier Paracoccus denitrificans did not produce N2 but evolved more than 10-fold more N2O than strains TR2 and K50 evolved. The isolates denitrified NO3 − with concomitant consumption of O2. These results indicated that strains TR2 and K50 are aerobic denitrifiers. These two isolates were taxonomically placed in the β subclass of the class Proteobacteria and were identified as P. stutzeri TR2 and Pseudomonas sp. strain K50. These strains should be useful for future investigations of the mechanisms of denitrifying bacteria that regulate N2O emission, the single-stage process for nitrogen removal, and microbial N2O emission into the ecosystem.

In-situ characterization of microbial community in an A/O submerged membrane bioreactor with nitrogen removal

2004 ◽  
Vol 50 (8) ◽  
pp. 41-48 ◽  
Author(s):  
A. Sofia ◽  
W.-T. Liu ◽  
S.L. Ong ◽  
W.J. Ng
Keyword(s):  
Bacterial Community ◽  
Nitrogen Removal ◽  
Membrane Bioreactor ◽  
Ammonia Oxidation ◽  
Paracoccus Denitrificans ◽  
Pseudomonas Stutzeri ◽  
Laboratory Scale ◽  
Negative Results

The bacterial community involved in removing nitrogen from sewage and their preferred DO environment within an anoxic/oxic membrane bioreactor (A/O MBR) was investigated. A continuously operated laboratory-scale A/O MBR was maintained for 360 d. At a sludge age of 150 d and a C/N ratio of 3.5, the system was capable of removing 88% of the influent nitrogen from raw wastewater through typical nitrogen removal transformations (i.e. aerobic ammonia oxidation and anoxic nitrate reduction). Characterization of the A/O MBR bacterial community was carried out using fluorescence in situ hybridization (FISH) techniques. FISH results further showed that Nitrosospira spp. and Nitrospira spp. were the predominant groups of ammonia and nitrite oxidizing group, respectively. They constituted up to 11% and 6% of eubacteria at DO below 0.05 mg/l (low DO), respectively, and about 14% and 9% of eubacteria at DO between 2–5 mg/l (sufficient DO), respectively, indicating preference of nitrifiers for a higher DO environment. Generally low counts of the genus Paracoccus were detected while negative results were observed for Paracoccus denitrificans, Alcaligenes spp, and Pseudomonas stutzeri under the low and sufficient DO environments. The overall results indicate that Nitrosospira spp., Nitrospira spp. and members of Paracoccus spp. can be metabolically functional in nitrogen removal in the laboratory-scale A/O MBR system.

Efficient total nitrogen removal from wastewater by Paracoccus denitrificans DYTN‐1

2020 ◽  
Vol 70 (4) ◽  
pp. 263-273
Author(s):  
Y. Zhao ◽  
W. Lu ◽  
Y. Liu ◽  
J. Wang ◽  
S. Zhou ◽  
...  
Keyword(s):  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Paracoccus Denitrificans ◽  
Total Nitrogen Removal

scholarly journals Effects of Exogenous N-Acyl-Homoserine Lactone as Signal Molecule on Nitrosomonas Europaea under ZnO Nanoparticle Stress

2019 ◽  
Vol 16 (16) ◽  
pp. 3003
Author(s):  
Junkang Wu ◽  
Huan Gao ◽  
Jinyu Ye ◽  
Yan Chang ◽  
Ran Yu ◽  
...  
Keyword(s):  
Nitrogen Removal ◽  
Membrane Integrity ◽  
Amoa Gene ◽  
Nitrosomonas Europaea ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
Zno Nanoparticle ◽  
Nano Zno ◽  
Monooxygenase Activity ◽  
The Impact

Despite the adverse effects of emerging ZnO nanoparticles (nano-ZnO) on wastewater biological nitrogen removal (BNR) systems being widely documented, strategies for mitigating nanoparticle (NP) toxicity impacts on nitrogen removal have not been adequately addressed. Herein, N-acyl-homoserine lactone (AHL)-based quorum sensing (QS) was investigated for its effects against nano-ZnO toxicity to a model nitrifier, Nitrosomonas europaea. The results indicated that AHL-attenuated nano-ZnO toxicity, which was inversely correlated with the increasing dosage of AHL from 0.01 to 1 µM. At 0.01 µM, AHL notably enhanced the tolerance of N. europaea cells to nano-ZnO stress, and the inhibited cell proliferation, membrane integrity, ammonia oxidation rate, ammonia monooxygenase activity and amoA gene expression significantly increased by 18.2 ± 2.1, 2.4 ± 0.9, 58.7 ± 7.1, 32.3 ± 1.7, and 7.3 ± 5.9%, respectively, after 6 h of incubation. However, increasing the AHL dosage compromised the QS-mediated effects and even aggravated the NPs’ toxicity effects. Moreover, AHLs, at all tested concentrations, significantly increased superoxide dismutase activity, indicating the potential of QS regulations to enhance cellular anti-oxidative stress capacities when facing NP invasion. These results provide novel insights into the development of QS regulation strategies to reduce the impact of nanotoxicity on BNR systems.

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