Characterization of amoA and hao Genes Responsible for Ammonia Oxidation Reaction in CANON System

2011 ◽  
Vol 183-185 ◽  
pp. 1014-1019
Author(s):  
Hai Yan Zou ◽  
Jun Li Huang ◽  
Fang Fang ◽  
Jin Song Guo
Keyword(s):  
Nitrogen Removal ◽  
Oxidation Reaction ◽  
High Efficiency ◽  
Ammonia Oxidation ◽  
Residual Activity ◽  
Maximum Activity ◽  
Ammonia Oxidizing Bacteria ◽  
Hydroxylamine Oxidoreductase ◽  
Optimum Ph

In this research the genes (amoA and hao) for ammonia monooxygenase (AMO) and hydroxylamine oxidoreductase (HAO) responsible for ammonia oxidation reaction in completely autotrophic nitrogen removal over nitrite process were cloned and sequenced, and the recombinant protein of AMO and HAO was expressed and characterized. The optimum temperature for AMO activity was 55 °C and more than 40% of the maximum activity was retained from 15-50 °C. The optimum pH for the enzyme was found to be pH 11.0. The highest activity for HAO was observed at 45 °C. More than 50% of the maximum activity was retained even at 55 °C. The dependence of HAO on pH was strong and only average 15% of residual activity left at pH ranging from 3.0-9.0. Study on the molecular and biochemistry properties of recombinant AMO and HAO will benefit for the manipulation of ammonia-oxidizing bacteria to achieve the goal of high efficiency of nitrogen removal.

scholarly journals Nitrification mainly driven by ammonia-oxidizing bacteria and nitrite-oxidizing bacteria in an anammox-inoculated wastewater treatment system

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jing Lu ◽  
Yiguo Hong ◽  
Ying Wei ◽  
Ji-Dong Gu ◽  
Jiapeng Wu ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Nitrogen Removal ◽  
High Throughput Sequencing ◽  
High Efficiency ◽  
Ammonia Oxidation ◽  
Ammonia Oxidizing Bacteria ◽  
Ammonium Oxidation ◽  
Strong Activity ◽  
Nitrite Oxidizing Bacteria

AbstractAnaerobic ammonium oxidation (anammox) process has been acknowledged as an environmentally friendly and time-saving technique capable of achieving efficient nitrogen removal. However, the community of nitrification process in anammox-inoculated wastewater treatment plants (WWTPs) has not been elucidated. In this study, ammonia oxidation (AO) and nitrite oxidation (NO) rates were analyzed with the incubation of activated sludge from Xinfeng WWTPs (Taiwan, China), and the community composition of nitrification communities were investigated by high-throughput sequencing. Results showed that both AO and NO had strong activity in the activated sludge. The average rates of AO and NO in sample A were 6.51 µmol L−1 h−1 and 6.52 µmol L−1 h−1, respectively, while the rates in sample B were 14.48 µmol L−1 h−1 and 14.59 µmol L−1 h−1, respectively. The abundance of the nitrite-oxidizing bacteria (NOB) Nitrospira was 0.89–4.95 × 1011 copies/g in both samples A and B, the abundance of ammonia-oxidizing bacteria (AOB) was 1.01–9.74 × 109 copies/g. In contrast, the abundance of ammonia-oxidizing archaea (AOA) was much lower than AOB, only with 1.28–1.53 × 105 copies/g in samples A and B. The AOA community was dominated by Nitrosotenuis, Nitrosocosmicus, and Nitrososphaera, while the AOB community mainly consisted of Nitrosomonas and Nitrosococcus. The dominant species of Nitrospira were Candidatus Nitrospira defluvii, Candidatus Nitrospira Ecomare2 and Nitrospira inopinata. In summary, the strong nitrification activity was mainly catalyzed by AOB and Nitrospira, maintaining high efficiency in nitrogen removal in the anammox-inoculated WWTPs by providing the substrates required for denitrification and anammox processes.

Immobilization and Characterization of Tannase and its Haze-removing

2009 ◽  
Vol 15 (6) ◽  
pp. 545-552 ◽  
Author(s):  
Erzheng Su ◽  
Tao Xia ◽  
Liping Gao ◽  
Qianying Dai ◽  
Zhengzhu Zhang
Keyword(s):  
Kinetic Parameter ◽  
High Activity ◽  
Green Tea ◽  
Storage Stability ◽  
Residual Activity ◽  
Black Tea ◽  
Optimum Temperature ◽  
Oolong Tea ◽  
Optimum Ph

Tannase was effectively immobilized on alginate by the method of crosslinking-entrapment-crosslinking with a high activity recovery of 76.6%. The properties of immobilized tannase were investigated. Its optimum temperature was determined to be 35 ° C, decreasing 10 °C compared with that of free enzyme, whereas the optimum pH of 5.0 did not change. The thermal and pH stabilities of immobilized tannase increased to some degree. The kinetic parameter, Km, for immobilized tannase was estimated to be 11.6 × 10-4 mol/L. Fe2+ and Mn2+ could activate the activity of immobilized tannase. The immobilized tannase was also applied to treat the tea beverage to investigate its haze-removing effect. The content of non-estern catechins in green tea, black tea and oolong tea increased by 52.17%, 12.94% and 8.83%, respectively. The content of estern catechins in green tea, oolong tea and black tea decreased by 20.0%, 16.68% and 5.04%, respectively. The anti-sediment effect of green tea infusion treated with immobilized tannase was significantly increased. The storage stability and reusability of the immobilized tannase were improved greatly, with 72.5% activity retention after stored for 42 days and 86.9% residual activity after repeatedly used for 30 times.

scholarly journals Nitrogen removal via a single-stage PN–Anammox process in a novel combined biofilm reactor

2017 ◽  
Vol 77 (6) ◽  
pp. 1483-1492 ◽  
Author(s):  
Yue-mei Han ◽  
Feng-xia Liu ◽  
Xiao-fei Xu ◽  
Zhuo Yan ◽  
Zhi-jun Liu
Keyword(s):  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Ammonia Oxidation ◽  
Biofilm Reactor ◽  
Nitrifying Bacteria ◽  
Anammox Bacteria ◽  
Ammonia Oxidizing Bacteria ◽  
High Ammonia ◽  
Total Nitrogen Removal ◽  
Anammox Process

Abstract This study developed a partial nitrification (PN) and anaerobic ammonia oxidation (Anammox) process for treating high-ammonia wastewater using an innovative biofilm system in which ammonia oxidizing bacteria grew on fluidized Kaldnes (K1) carriers and Anammox bacteria grew on fixed acryl resin carriers. The airlift loop biofilm reactor (ALBR) was stably operated for more than 4 months under the following conditions: 35 ± 2 °C, pH 7.5–8.0 and dissolved oxygen (DO) of 0.5–3.5 mg/L. The results showed that the total nitrogen removal efficiency reached a maximum of 75% and the total nitrogen removal loading rate was above 0.4 kg/(d·m3). DO was the most efficient control parameter in the mixed biofilm system, and values below 1.5 mg/L were observed in the riser zone for the PN reaction, while values below 0.8 mg/L were observed in the downer zone for the Anammox reaction. Scanning electron microscopy and Fluorescence In Situ Hybridization images showed that most of the nitrifying bacteria were distributed on the K1 carriers and most of the Anammox bacteria were distributed within the acryl resin carriers. Therefore, the results indicate that the proposed combined biofilm system is easy to operate and efficient for the treatment of high-ammonia wastewater.

scholarly journals Ecophysiological Characterization of Ammonia-Oxidizing Archaea and Bacteria from Freshwater

2012 ◽  
Vol 78 (16) ◽  
pp. 5773-5780 ◽  
Author(s):  
Elizabeth French ◽  
Jessica A. Kozlowski ◽  
Maitreyee Mukherjee ◽  
George Bullerjahn ◽  
Annette Bollmann
Keyword(s):  
Growth Rates ◽  
Ammonia Oxidation ◽  
Light Exposure ◽  
Enrichment Culture ◽  
Ammonia Oxidizing Bacteria ◽  
Content Type ◽  
Ammonia Oxidizing Archaea ◽  
Group I ◽  
Nitrosomonas Oligotropha

ABSTRACTAerobic biological ammonia oxidation is carried out by two groups of microorganisms, ammonia-oxidizing bacteria (AOB) and the recently discovered ammonia-oxidizing archaea (AOA). Here we present a study using cultivation-based methods to investigate the differences in growth of three AOA cultures and one AOB culture enriched from freshwater environments. The strain in the enriched AOA culture belong to thaumarchaeal group I.1a, with the strain in one enrichment culture having the highest identity with “CandidatusNitrosoarchaeum koreensis” and the strains in the other two representing a new genus of AOA. The AOB strain in the enrichment culture was also obtained from freshwater and had the highest identity to AOB from theNitrosomonas oligotrophagroup (Nitrosomonascluster 6a). We investigated the influence of ammonium, oxygen, pH, and light on the growth of AOA and AOB. The growth rates of the AOB increased with increasing ammonium concentrations, while the growth rates of the AOA decreased slightly. Increasing oxygen concentrations led to an increase in the growth rate of the AOB, while the growth rates of AOA were almost oxygen insensitive. Light exposure (white and blue wavelengths) inhibited the growth of AOA completely, and the AOA did not recover when transferred to the dark. AOB were also inhibited by blue light; however, growth recovered immediately after transfer to the dark. Our results show that the tested AOB have a competitive advantage over the tested AOA under most conditions investigated. Further experiments will elucidate the niches of AOA and AOB in more detail.

scholarly journals Performance and microbial community of the CANON process in a sequencing batch membrane bioreactor with elevated COD/N ratios

2020 ◽  
Vol 81 (1) ◽  
pp. 138-147
Author(s):  
Xiaoling Zhang ◽  
Xincong Liu ◽  
Meng Zhang
Keyword(s):  
Organic Matter ◽  
Microbial Community ◽  
Nitrogen Removal ◽  
Membrane Bioreactor ◽  
Ammonia Oxidation ◽  
Heterotrophic Bacteria ◽  
Removal Rate ◽  
Ammonia Oxidizing Bacteria ◽  
Anaerobic Ammonia Oxidation ◽  
Canon Process

Abstract In this study, the effects of elevated chemical oxygen demand/nitrogen (COD/N) ratios on nitrogen removal, production and composition of the extracellular polymer substances (EPS) and microbial community of a completely autotrophic nitrogen removal via nitrite (CANON) process were studied in a sequencing batch membrane bioreactor (SBMBR). The whole experiment was divided into two stages: the CANON stage (without organic matter in influent) and the simultaneous partial nitrification, anaerobic ammonia oxidation and denitrification (SNAD) stage (with organic matter in influent). When the inflow ammonia nitrogen was 420 mg/L and the COD/N ratio was no higher than 0.8, the addition of COD was helpful to the CANON process; the total nitrogen removal efficiency (TNE) was improved from approximately 65% to more than 75%, and the nitrogen removal rate (NRR) was improved from approximately 0.255 kgN/(m3·d) to approximately 0.278 kgN/(m3•d), while the TNE decreased to 60%, and the NRR decreased to 0.236 kgN/(m3•d) when the COD/N ratio was elevated to 1.0. For the EPS, the amounts of soluble EPS (SEPS) and loosely bound EPS (LB-EPS) were both higher in the CANON stage than in the SNAD stage, while the amount of tightly bound EPS (TB-EPS) in the SNAD stage was significantly higher due to the proliferation of heterotrophic bacteria. The metagenome sequencing technique was used to analyse the microbial community in the SBMBR. The results showed that the addition of COD altered the structure of the bacterial community in the SBMBR. The amounts of Candidatus ‘Anammoxoglobus’ of anaerobic ammonia oxidation bacteria (AAOB) and Nitrosomonas of ammonia oxidizing bacteria (AOB) both decreased significantly, and Nitrospira of nitrite oxidizing bacteria (NOB) was always in the reactor, although the amount changed slightly. A proliferation of denitrifiers related to the genera of Thauera, Dokdonella and Azospira was found in the SBMBR.

Nitrous oxide production by lithotrophic ammonia-oxidizing bacteria and implications for engineered nitrogen-removal systems

2011 ◽  
Vol 39 (6) ◽  
pp. 1832-1837 ◽  
Author(s):  
Kartik Chandran ◽  
Lisa Y. Stein ◽  
Martin G. Klotz ◽  
Mark C.M. van Loosdrecht
Keyword(s):  
Nitrous Oxide ◽  
Nitrogen Removal ◽  
Ammonia Oxidation ◽  
Wastewater Treatment Plants ◽  
N2o Emissions ◽  
Ammonia Oxidizing Bacteria ◽  
N2o Production ◽  
Nitrogen Emissions ◽  
Greenhouse Gas Inventories ◽  
Nitrogen Concentrations

Chemolithoautotrophic AOB (ammonia-oxidizing bacteria) form a crucial component in microbial nitrogen cycling in both natural and engineered systems. Under specific conditions, including transitions from anoxic to oxic conditions and/or excessive ammonia loading, and the presence of high nitrite (NO2−) concentrations, these bacteria are also documented to produce nitric oxide (NO) and nitrous oxide (N2O) gases. Essentially, ammonia oxidation in the presence of non-limiting substrate concentrations (ammonia and O2) is associated with N2O production. An exceptional scenario that leads to such conditions is the periodical switch between anoxic and oxic conditions, which is rather common in engineered nitrogen-removal systems. In particular, the recovery from, rather than imposition of, anoxic conditions has been demonstrated to result in N2O production. However, applied engineering perspectives, so far, have largely ignored the contribution of nitrification to N2O emissions in greenhouse gas inventories from wastewater-treatment plants. Recent field-scale measurements have revealed that nitrification-related N2O emissions are generally far higher than emissions assigned to heterotrophic denitrification. In the present paper, the metabolic pathways, which could potentially contribute to NO and N2O production by AOB have been conceptually reconstructed under conditions especially relevant to engineered nitrogen-removal systems. Taken together, the reconstructed pathways, field- and laboratory-scale results suggest that engineering designs that achieve low effluent aqueous nitrogen concentrations also minimize gaseous nitrogen emissions.

scholarly journals Purification and characterization of amylase from local isolate Pseudomonas sp.SPH4

2012 ◽  
Vol 6 (1) ◽  
pp. 69-79
Author(s):  
Hala M. Ali ◽  
Ghazi M. Aziz
Keyword(s):  
Enzyme Activity ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Silver Ions ◽  
Enzyme Characterization ◽  
Maximum Activity ◽  
Mercury Ions ◽  
Local Isolate ◽  
Optimum Ph

The amylase produced from local isolate Pseudomonas sp. SPH4 was purified by precipitation with 30% saturation ammonium sulphate, followed by ion-exchange chromotography using DEAE-cellulose column, and Gel filtration using Sephacryl S-300 column.The two iso-enzymes (a, b) were purified to (2.83, 3.47) times in the last step with an enzymes yields of (32.36, 76.34)% respectively. Enzyme characterization of the two iso-enzymes indicated that the optimum pH for the two iso-enzymes a and b were (7, 7.5) respectively, while the optimum pH for the iso-enzymes stability were (6.5, 7) respectively. The maximum activity for iso-enzymes (a, b) appeared at 45ºC and stable for 15 min at 30-50ºC and lost approximately 50% of it's activity at rang above 75ºC. Enzyme characterization results showed that the chlorides of silver and mercury had inhibitory effect on enzyme activity, the remaining enzyme activity for the iso-enzymes (a, b) were (46.66, 36.36)% for silver ions and (41.33, 33.63)% for mercury ions at 5 mM respectively, and (28, 28.18)% for silver ions and (25.33, 19.09)% for mercury ions at 10 mM respectively. The iso-enzymes a and b were affected by chelating agent ethylene diamine tetra acetic acid (EDTA) at concentration 2mM the remaining activity (45.33, 43.63)% respectively, and 5mM the remaining activity (28, 28.18)% respectivily, and these iso-enzymes (a, b) refered to metalloenzymes. The iso-enzymes (a, b) were kept their activity when treated by reducing agent (2-mercaptoethanol) at 2 mM the remaining activity (92, 92.72)% respectively, and 5 mM the remaining activity (85.3, 89.09)% respectivily. The iso-enzymes (a, b) were kept their activity when treated by phenyl methyl sulphonyl fluoride (PMSF) at concentration 1mM the remaining activity (93.33, 90.90)% respectivily,and 5 mM the remaining activity (90.66, 87.27)% respectivily, and these indicated that these iso-enzymes didnot referred to serineamylases group.

The influence of trace NO2 on the kinetics of ammonia oxidation and the characteristics of nitrogen removal from wastewater

2010 ◽  
Vol 62 (5) ◽  
pp. 1037-1044 ◽  
Author(s):  
Daijun Zhang ◽  
Qing Cai ◽  
Bo Zu ◽  
Cui Bai ◽  
Ping Zhang
Keyword(s):  
Nitrogen Removal ◽  
Oxidation Rate ◽  
Ammonia Oxidation ◽  
Batch Reactor ◽  
Synthetic Wastewater ◽  
Ammonia Oxidizing Bacteria ◽  
Oxidation Activity ◽  
Batch Tests ◽  
Denitrification Activity ◽  
Ammonia Oxidation Rate

Ammonia oxidizing bacteria-enriched sludge was obtained in a sequencing batch reactor with synthetic wastewater. Batch tests of ammonia oxidation were carried out with the sludge, in the presence of only trace NO2 and in the presence of O2 and trace NO2, respectively. The Andrews model is used to describe NO2-dependent ammonia oxidation. The maximum ammonia oxidation rate of 139.11 mg N·(g sludge COD h)−1, occurred in the presence of 21% O2 and 100 ppm NO2, which was 3 times higher than the aerobic ammonia oxidation rate without NO2. The kinetic model of ammonia oxidation in the presence of O2 and trace NO2 is developed, and the function of NO2 apparently enhancing ammonia oxidation is suggested. The maximal nitrogen removel of 34.19% occurred at the 21% O2 and 100 ppm NO2 in the mixed gases. Nitrogen removal principally depended on the denitrification activity and NO2-dependent ammonia oxidation activity of ammonia-oxidizing bacteria (AOB).

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.

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