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Denitrifying bacteria

William D Orsi, Marco J L Coolen, Cornelia Wuchter, Lijun He, Kuldeep D More, Xabier Irigoien, Guillem Chust, Carl Johnson, Jordon D Hemingway, Mitchell Lee, Valier Galy, Liviu Giosan
Selection of microorganisms in marine sediment is shaped by energy-yielding electron acceptors for respiration that are depleted in vertical succession. However, some taxa have been reported to reflect past depositional conditions suggesting they have experienced weak selection after burial. In sediments underlying the Arabian Sea oxygen minimum zone (OMZ), we performed the first metagenomic profiling of sedimentary DNA at centennial-scale resolution in the context of a multi-proxy paleoclimate reconstruction...
July 20, 2017: Scientific Reports
V A J Rodrigues, E F A Mac Conell, D F C Dias, M von Sperling, J C de Araújo, J L Vasel
Accumulated sludge in polishing (maturation) ponds reduces the hydraulic retention time (smaller useful volume), and this could potentially lead to a decrease in performance. However, settled biomass, present in the sediments, can contribute to nitrogen removal by different mechanisms such as nitrification and denitrification. This study investigated the influence of the bottom sludge present in a shallow maturation pond treating the effluent from an anaerobic reactor on the nitrification and denitrification processes...
July 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Yihua Sun, Paul De Vos, Anne Willems
Until recently, it has not been generally known that some bacteria can contain the gene inventory for both denitrification and dissimilatory nitrate (NO3(-))/nitrite (NO2(-)) reduction to ammonium (NH4(+)) (DNRA). Detailed studies of these microorganisms could shed light on the differentiating environmental drivers of both processes without interference of organism-specific variation. Genome analysis of Bacillus azotoformans LMG 9581(T) shows a remarkable redundancy of dissimilatory nitrogen reduction, with multiple copies of each denitrification gene as well as DNRA genes nrfAH, but a reduced capacity for nitrogen assimilation, with no nas operon nor amtB gene...
July 19, 2017: Antonie Van Leeuwenhoek
Hongliang Dai, Yifeng Wu, Lihong Peng, Zheqin Dai, Xiang Li, Xiwu Lu
A sequencing batch reactor was operated to study the effects of influent Ca(2+) on the efficiency, bacterial population, and microbial metabolism of denitrifying phosphorus removal system. Results showed that high Ca(2+) loading (≥80mg/L) significantly inhibited the performance of simultaneous nitrogen and phosphorus removal. The abundance of phosphorus removal-related organisms (Dechloromonas and Candidatus Accumulibacter) decreased with increasing Ca(2+) concentration from 20 to 140mg/L, while the abundance of glycogen-accumulating organisms and other bacteria increased...
July 8, 2017: Bioresource Technology
Gang Guo, Di Wu, Tianwei Hao, Hamish Robert Mackey, Li Wei, Guanghao Chen
The performance of the denitrifying sulfur conversion-associated enhanced biological phosphorus removal (DS-EBPR) process tends to be unstable and requires further study and development. This in turn requires extensive study of the anaerobic metabolism in terms of its stoichiometry and kinetics. This study evaluates the corresponding responses of DS-EBPR to pH, as it significantly influences both stoichiometry and biochemical kinetics. The impacts of five representative pH values ranging between 6.5 and 8.5 on the anaerobic metabolism were investigated, followed by identification of the optimal pH for performance optimization...
July 12, 2017: Water Research
Shuang He, Yingmu Wang, Chuansong Li, Yancheng Li, Jian Zhou
The advanced treatment of secondary effluent was conducted in a two-stage deep sequencing constructed wetland (DSCW) which comprised a denitrification chamber (W1) and a nitrification chamber (W2). The results showed that a superior NO3(-)-N removal rate was observed in W1 with a C/N ratio of 6.5, and a high NH4(+)-N removal rate was obtained when the W2 was operated with 6-h duration of idle. In the long-term operation for 45days, the two-stage DSCW pilot system achieved high and stable removal of TN, NH4(+)-N and NO3(-)-N, which were 92...
June 29, 2017: Bioresource Technology
Tingting Tian, Nora F Y Tam, Qijie Zan, S G Cheung, Paul K S Shin, Y S Wong, Li Zhang, Zhanghe Chen
Constructed mangrove wetland has been used for wastewater treatment but its long-term performance has not been reported. One-year monitoring of a 10-years old horizontal subsurface-flow constructed mangrove wetland consisting of three belts, two with mangrove plants and one without, revealed that the system maintained high and stable removal percentages of organic matter and nutrients, and planted belts performed better than unplanted control. Substrates in belts planted with Aegiceras corniculatum or Kandelia obovata had higher abundance of ammonifiers, nitrifiers and denitrifiers but lower total heterotrophic bacteria than unplanted substrate...
July 12, 2017: Marine Pollution Bulletin
Jianhua Zhang, Qiong Zhang, Xiyao Li, Yuanyuan Miao, Yawen Sun, Miao Zhang, Yongzhen Peng
Obtaining desirable partial nitritation (PN) is crucial for successful application of the combined PN and anammox process. In this study, the partial nitritation and simultaneously phosphorus removal (PNSPR)(1) granular sludge reactor treating low-strength domestic sewage was rapidly started up in 67days through seeding denitrifying phosphorus removal (DPR)(2) sludge. The nitrite/ammonium ratio in effluent was approximately 1 and the nitrite accumulation rate (NAR) was more than 95%, about 93% of orthophosphate was removed...
June 26, 2017: Bioresource Technology
Sam Horrell, Demet Kekilli, Richard W Strange, Michael A Hough
Copper nitrite reductases (CuNiR) carry out the first committed step of the denitrification pathway of the global nitrogen cycle, the reduction of nitrite (NO2(-)) to nitric oxide (NO). As such, they are of major agronomic and environmental importance. CuNiRs occur primarily in denitrifying soil bacteria which carry out the overall reduction of nitrate to dinitrogen. In this article, we review the insights gained into copper nitrite reductase (CuNiR) function from three dimensional structures. We particularly focus on developments over the last decade, including insights from serial femtosecond crystallography using X-ray free electron lasers (XFELs) and from the recently discovered 3-domain CuNiRs...
July 12, 2017: Metallomics: Integrated Biometal Science
Vani Mohit, Alexander Culley, Connie Lovejoy, Frédéric Bouchard, Warwick F Vincent
Shallow lakes are common across the Arctic landscape and their ecosystem productivity is often dominated by benthic, cyanobacterial biofilms. Many of these water bodies freeze to the bottom and are biologically inactive during winter, but full freeze-up is becoming less common with Arctic warming. Here we analyzed the microbiome structure of newly discovered biofilms at the deepest site of a perennially ice-covered High Arctic lake as a model of polar microbial communities that remain unfrozen throughout the year...
2017: NPJ Biofilms and Microbiomes
Xin Sun, Amal Jayakumar, Bess B Ward
The ozone-depleting and greenhouse gas, nitrous oxide (N2O), is mainly consumed by the microbially mediated anaerobic process, denitrification. N2O consumption is the last step in canonical denitrification, and is also the least O2 tolerant step. Community composition of total and active N2O consuming bacteria was analyzed based on total (DNA) and transcriptionally active (RNA) nitrous oxide reductase (nosZ) genes using a functional gene microarray. The total and active nosZ communities were dominated by a limited number of nosZ archetypes, affiliated with bacteria from marine, soil and marsh environments...
2017: Frontiers in Microbiology
Fabio Polesel, Elena Torresi, Luca Loreggian, Mònica Escolà Casas, Magnus Christensson, Kai Bester, Benedek Gy Plósz
Due to the limited efficiency of conventional biological treatment, innovative solutions are being explored to improve the removal of trace organic chemicals in wastewater. Controlling biomass exposure to growth substrate represents an appealing option for process optimization, as substrate availability likely impacts microbial activity, hence organic trace chemical removal. This study investigated the elimination of pharmaceuticals in pre-denitrifying moving bed biofilm reactors (MBBRs), where biofilm exposure to different organic substrate loading and composition was controlled by reactor staging...
June 26, 2017: Water Research
Yan Gao, Chengcheng Wang, Weiguo Zhang, Panpan Di, Neng Yi, Chengrong Chen
Bacterial communities in rivers receiving untreated domestic wastewater may show specific spatial assemblage patterns due to a wide range of physicochemical conditions created by periodic algal bloom. However, there are significant gaps in understanding environmental forces that drive changes in microbial assemblages in polluted rivers. In this study, we applied high-throughput sequencing of 16S rRNA gene amplicons to perform comprehensive spatio-temporal profiling of bacterial community structure in a local river segment receiving domestic wastewater discharge in southeast China...
July 5, 2017: Environmental Pollution
Tomoko Yasuda, Miyoko Waki, Yasuyuki Fukumoto, Dai Hanajima, Kazutaka Kuroda, Kazuyoshi Suzuki
The potential denitrification activity and the composition of the denitrifying bacterial community in a full-scale rockwool biofilter used for treating livestock manure composting emissions were analyzed. Packing material sampled from the rockwool biofilter was anoxically batch-incubated with (15)N-labeled nitrate in the presence of different electron donors (compost extract, ammonium, hydrogen sulfide, propionate, and acetate), and responses were compared with those of activated sludge from a livestock wastewater treatment facility...
July 7, 2017: Applied Microbiology and Biotechnology
Chuanqi Zhao, Gang Wang, Xiaochen Xu, Yuesuo Yang, Fenglin Yang
In this study, an oxygen-limiting membrane bioreactor (MBR) with recirculation of biogas for relieving membrane fouling was successfully operated to realize the simultaneous partial nitrification, anammox and denitrification (SNAD) process. The MBR operation was considered effective in the long-term test with total nitrogen (TN) and COD removal efficiencies of 94.86% and 98.91%, respectively. Membrane fouling was significantly alleviated due to the recirculation of biogas and the membrane had been cleaned four times with a normal filtration period of 52 d...
July 6, 2017: Environmental Technology
Jing Zhao, Lijuan Feng, Jincheng Dai, Guangfeng Yang, Jun Mu
Each kind of conventional plastic filler (polyurethane filler, SPR-1 suspension filler, TA-II elastic filler and sphere filler) coupled with alkaline pretreated corncob (A.H.corncob) was applied in each bioreactor system for treating polluted water with nitrate and organics. Results demonstrated that addition of A.H.corncob could achieve simultaneous removal of nitrogen and organics, and coupling of SPR-1 suspension filler with A.H.corncob (R2) had the best performance. In coupling system of R2, the total nitrogen (TN) removal rate improved from below 10% to 55...
July 5, 2017: Biodegradation
Xi Li, Miaomiao Zhang, Feng Liu, Liang Chen, Yuyuan Li, Yong Li, Rulin Xiao, Jinshui Wu
Surface flow constructed wetlands (SFCWs) planted with Myriophyllum elatinoides for treatment of swine wastewater were examined to evaluate the effect of season, segment (site S1, S2, and S3), and treatment (100mgL(-1) TN, T1; 300mgL(-1) TN, T2; 500mgL(-1) TN, T3) on the activity, and abundances of nitrifying and, denitrifying microorganisms, and on the abundance of sediment bacteria. The activity and abundances of nitrifiers, denitrifiers, and the abundance of bacteria were the highest in T3 samples, especially in S1 (P<0...
June 20, 2017: Bioresource Technology
Kaixin Yi, Dongbo Wang, QiYang, Xiaoming Li, Hongbo Chen, Jian Sun, Hongxue An, Liqun Wang, Yongchao Deng, Jun Liu, Guangming Zeng
In this work, both short-term and long-term experiments were therefore conducted to assess the effects of ciprofloxacin (0.2 and 2mg·L(-1)) on wastewater nutrient removal. The results showed that both levels of ciprofloxacin had no acute and chronic adverse effects on the surface integrity and viability of activated sludge. Short-term exposure to all the ciprofloxacin levels induced negligible influences on wastewater nutrient removal. However, the prolonged exposure to ciprofloxacin decreased total phosphorus and nitrogen removal efficiencies from 96...
June 29, 2017: Science of the Total Environment
Hou Yu, Hiroyuki Kashima, John M Regan, Abid Hussain, Elsayed Elbeshbishy, Hyung-Sool Lee
Monod kinetic parameters provide information required for kinetic analysis of anaerobic oxidation of methane coupled to denitrification (AOM-D). This information is critical for engineering AOM-D processes in wastewater treatment facilities. We first experimentally determined Monod kinetic parameters for an AOM-D enriched culture and obtained the following values: maximum specific growth rate (μmax) 0.121/d, maximum substrate-utilization rate (qmax) 28.8mmol CH4/g cells-d, half maximum-rate substrate concentration (Ks) 83μΜ CH4, growth yield (Y) 4...
September 2017: Enzyme and Microbial Technology
Cong Du, Chongwei Cui, Shan Qiu, Shanwen Xu, Shengnan Shi, Thangavel Sangeetha, Fang Ma
Bioaugmentation is substantially determined by pre-attached communities in biological stuffing systems. However, the inevitable changes of microbial community shift occurred between pre-attached microorganisms on stuffing material and other existing communities in wastewater. Targeting at nitrogen removal in aerobic denitrification reactors, biological augmentation was built by polyurethane supporting material and aerobic denitrification bacteria of Pseudomonas stutzeri strains were primarily colonized. The total nitrogen removal reached a high efficiency of 77 ± 6%, resulting from a relative high nitrate removal (90%) and a low nitrite production of 24 mg l(-1)...
July 2017: World Journal of Microbiology & Biotechnology
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