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Denitrifying bacteria

Linlin Yao, Yanxin Wang, Lei Tong, Yamin Deng, Yonggang Li, Yiqun Gan, Wei Guo, Chuangju Dong, Yanhua Duan, Ke Zhao
The occurrence of 14 antibiotics (fluoroquinolones, tetracyclines, macrolides and sulfonamides) in groundwater and surface water at Jianghan Plain was investigated during three seasons. The total concentrations of target compounds in the water samples were higher in spring than those in summer and winter. Erythromycin was the predominant antibiotic in surface water samples with an average value of 1.60μg/L, 0.772μg/L and 0.546μg/L respectively in spring, summer and winter. In groundwater samples, fluoroquinolones and tetracyclines accounted for the dominant proportion of total antibiotic residues...
October 13, 2016: Ecotoxicology and Environmental Safety
Upendra Kumar, J Berliner, Totan Adak, Prakash C Rath, Avro Dey, Somnath S Pokhare, Nitiprasad N Jambhulkar, P Panneerselvam, Anjani Kumar, Shyamranjan D Mohapatra
Application of pesticide in agricultural fields is "unnecessary evil" for non-target microflora and fauna. Hence, to identify the safer pesticide molecules against non-target microbes, a long-term pesticide experiment was initiated at National Rice Research Institute, Cuttack, India. In the present study, the effect of continuous application of chlorpyrifos (0.5kgha(-1)) in rice fields on non-target groups of soil microbes and nematodes was studied for seven seasons (four wet and three dry seasons) during 2009-2013...
October 13, 2016: Ecotoxicology and Environmental Safety
Yun-Feng Duan, Xian-Wang Kong, Andreas Schramm, Rodrigo Labouriau, Jørgen Eriksen, Søren O Petersen
: Grassland cultivation can mobilize large pools of N in the soil, with a potential for N leaching and N2O emissions. Spraying with the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) before cultivation was simulated with soil columns where residue distribution corresponded to ploughing or rotovation, to study effects of soil-residue contact on N transformations. DMPP was sprayed on above-ground parts of ryegrass and white clover before incorporation. During a 42-day incubation, soil mineral N dynamics, potential ammonia oxidation (PAO) and denitrifying enzyme activity (DEA), nitrifier and denitrifier populations, and N2O emissions were investigated...
October 14, 2016: Applied and Environmental Microbiology
Zhao-Wei Ding, Yong-Ze Lu, Liang Fu, Jing Ding, Raymond J Zeng
In this study, the coculture system of denitrifying anaerobic methane oxidation (DAMO) microbes and anaerobic ammonium oxidation (anammox) bacteria was successfully enriched in a hollow-fiber membrane biofilm reactor (HfMBR) using freshwater sediment as the inoculum. The maximal removal rates of nitrate and ammonium were 78 mg N/L/day (131 mg N/m(2)/day) and 26 mg N/L/day (43 mg N/m(2)/day), respectively. Due to the high rate of methane mass transfer in HfMBR, the activity of DAMO archaea continued to increase during the enrichment period, indicating that HfMBR could be a powerful tool to enrich DAMO microorganisms...
October 12, 2016: Applied Microbiology and Biotechnology
Yue Yuan, Jinjin Liu, Bin Ma, Ye Liu, Bo Wang, Yongzhen Peng
This study presents a novel strategy to improve the removal efficiency of nitrogen and phosphorus from municipal wastewater by feeding sequencing batch reactor (SBR) with sludge alkaline fermentation products as carbon sources. The performances of two SBRs treating municipal wastewater (one was fed with sludge fermentation products; F-SBR, and the other without sludge fermentation products; B-SBR) were compared. The removal efficiencies of total nitrogen (TN) and phosphorus (PO4(3-)-P) were found to be 82.9% and 96...
October 8, 2016: Bioresource Technology
Wei Li, Xiao-Yu Lin, Jun-Jie Chen, Chao-Yang Cai, Ghulam Abbas, Zhi-Qiang Hu, He-Ping Zhao, Ping Zheng
Denitratation (nitrite produced from nitrate), has the potential applications in wastewater treatment by combining with ANAMMOX process. The occurrence of denitratation has been shown to be effected qualitatively by various parameters in the environment. A more quantitative understanding can be obtained using enrichment cultures in lab-scale experiments, yet information on the enrichment of functional microorganisms responsible for denitratation is lacking. In this study, a stable denitratation-dominated culture was obtained from methylotrophic denitrifying culture...
October 6, 2016: Applied Microbiology and Biotechnology
Jessica A Lee, Christopher A Francis
Denitrifying bacteria play a critical role in the estuarine nitrogen cycle. Through the transformation of nitrate into nitrogen gas, these organisms contribute to the loss of bioavailable (i.e., fixed) nitrogen from low-oxygen environments such as estuary sediments. Denitrifiers have been shown to vary in abundance and diversity across the spatial environmental gradients that characterize estuaries, such as salinity and nitrogen availability; however, little is known about how their communities change in response to temporal changes in those environmental properties...
October 5, 2016: Microbial Ecology
B L Read-Daily, F Sabba, J P Pavissich, R Nerenberg
Nitrous oxide (N2O) is a powerful greenhouse gas emitted from wastewater treatment, as well as natural systems, as a result of biological nitrification and denitrification. While denitrifying bacteria can be a significant source of N2O, they can also reduce N2O to N2. More information on the kinetics of N2O formation and reduction by denitrifying bacteria is needed to predict and quantify their impact on N2O emissions. In this study, kinetic parameters were determined for Paracoccus pantotrophus, a common denitrifying bacterium...
December 2016: AMB Express
Haryun Kim, Hee-Sung Bae, K Ramesh Reddy, Andrew Ogram
River tributaries are ecologically important environments that function as sinks of inorganic nitrogen. To gain greater insight into the nitrogen cycle (N-cycle) in these environments, the distributions and activities of microbial populations involved in the N-cycle were studied in riparian and stream sediments of the Santa Fe River (SFR) tributaries located in northern Florida, USA. Riparian sediments were characterized by much higher organic matter content, and extracellular enzyme activities, including cellobiohydrolase, β-d-glucosidase, and phenol oxidase than stream sediments...
September 30, 2016: Water Research
Johannes F Imhoff
During the past decades, tremendous advances have been made in the possibilities to study the diversity of microbial communities in the environment. The development of methods to study these communities on the basis of 16S rRNA gene sequences analysis was a first step into the molecular analysis of environmental communities and the study of biodiversity in natural habitats. A new dimension in this field was reached with the introduction of functional genes of ecological importance and the establishment of genetic tools to study the diversity of functional microbial groups and their responses to environmental factors...
May 24, 2016: Microorganisms
V J Inglezakis, S Malamis, A Omirkhan, J Nauruzbayeva, Z Makhtayeva, T Seidakhmetov, A Kudarova
In this work, the inhibitory effect of cyanide, phenol and 4-nitrophenol on the activated sludge process was investigated. The inhibition of the aerobic oxidation of organic matter, nitrification and denitrification were examined in batch reactors by measuring the specific oxygen uptake rate (sOUR), the specific ammonium uptake rate (sAUR) and the specific nitrogen uptake rate (sNUR) respectively. The tested cyanide, phenol and 4-nitrophenol concentrations were 0.2-1.7 mg/L, 4.8-73.1 mg/L and 8.2-73.0 mg/L respectively...
September 25, 2016: Journal of Environmental Management
Xi-Jun Xu, Chuan Chen, Ai-Jie Wang, Bing-Jie Ni, Wan-Qian Guo, Ye Yuan, Cong Huang, Xu Zhou, Dong-Hai Wu, Duu-Jong Lee, Nan-Qi Ren
A mathematical model of carbon, nitrogen and sulfur removal (C-N-S) from industrial wastewater was constructed considering the interactions of sulfate-reducing bacteria (SRB), sulfide-oxidizing bacteria (SOB), nitrate-reducing bacteria (NRB), facultative bacteria (FB), and methane producing archaea (MPA). For the kinetic network, the bioconversion of C-N by heterotrophic denitrifiers (NO3(-)→NO2(-)→N2), and that of C-S by SRB (SO4(2-)→S(2-)) and SOB (S(2-)→S(0)) was proposed and calibrated based on batch experimental data...
August 31, 2016: Journal of Hazardous Materials
Ken Meerbergen, Maarten Van Geel, Michael Waud, Kris A Willems, Raf Dewil, Jan Van Impe, Lise Appels, Bart Lievens
It is assumed that microbial communities involved in the biological treatment of different wastewaters having a different chemical composition harbor different microbial populations which are specifically adapted to the environmental stresses encountered in these systems. Yet, little is known about the composition of these microbial communities. Therefore, the aim of this study was to assess the microbial community composition over two seasons (winter and summer) in activated sludge from well-operating textile wastewater treatment plants (WWTPs) in comparison with municipal WWTPs, and to explain observed differences by environmental variables...
September 25, 2016: MicrobiologyOpen
Agnieszka Cydzik-Kwiatkowska, Paulina Rusanowska, Magdalena Zielińska, Katarzyna Bernat, Irena Wojnowska-Baryła
A technological system was developed for efficient nitrogen removal from real digester supernatant in a single reactor with shortened aeration to increase the economical aspects of wastewater treatment. The supernatant (600 mg TKN/L, low COD/N ratio of 2.2) was treated in batch reactors with aerobic granules (GSBRs) to test how one, two, or three non-aeration phases and acetate pulse feeding in the cycle affect the morphological and microbial properties of biomass. Introduction of one non-aeration phase in the cycle increased nitrogen removal efficiency by 11 % in comparison with constantly aerated GSBR...
September 23, 2016: Environmental Science and Pollution Research International
Marie Simonin, Agnès Richaume, Julien P Guyonnet, Audrey Dubost, Jean M F Martins, Thomas Pommier
Soils are facing new environmental stressors, such as titanium dioxide nanoparticles (TiO2-NPs). While these emerging pollutants are increasingly released into most ecosystems, including agricultural fields, their potential impacts on soil and its function remain to be investigated. Here we report the response of the microbial community of an agricultural soil exposed over 90 days to TiO2-NPs (1 and 500 mg kg(-1) dry soil). To assess their impact on soil function, we focused on the nitrogen cycle and measured nitrification and denitrification enzymatic activities and by quantifying specific representative genes (amoA for ammonia-oxidizers, nirK and nirS for denitrifiers)...
2016: Scientific Reports
Massimo Raboni, Vincenzo Torretta
A conventional biotrickling filter for airborne ammonia nitrification has been modified, by converting the liquid sump into a biological denitrifying reactor. The biotrickling filter achieves an average ammonia removal efficiency of 92.4 %, with an empty bed retention time (EBRT) equal to 36 s and an average ammonia concentration of 54.7 mg Nm(-3) in the raw air stream. The denitrification reactor converts ammonia into inert gas N2, in addition to other important advantages connected to the alkaline character of the biochemical pathway of the denitrifying bacteria...
September 20, 2016: Environmental Science and Pollution Research International
Catiane Pelissari, Cristina Ávila, Camila Maria Trein, Joan García, Rafael Dultra de Armas, Pablo Heleno Sezerino
The aim of this study was to characterize the nitrogen transforming bacterial communities within a partially saturated vertical subsurface flow constructed wetland (VF) treating urban wastewater in southern Brazil. The VF had a surface area of 3144m(2), and was divided into four wetland cells, out of which two were operated while the other two rested, alternating cycles of 30days. The nitrifying and denitrifying bacterial communities were characterized in wetland cell 3 (764m(2) surface area) over a period of 12months by using the FISH technique...
September 15, 2016: Science of the Total Environment
Asma Ben Rajeb, Inès Mehri, Houda Nasr, Afef Najjari, Neila Saidi, Abdennaceur Hassen
Biological treatment systems use the natural processes of ubiquitous organisms to remove pollutants and improve the water quality before discharge to the environment. In this paper, the nitrification/denitrification reactor allowed a reduction in organic load, but offered a weak efficiency in nitrate reduction. However, the additions of the activated sludge in the reactor improve this efficiency. A decrease of NO3(-)-N values from 13.3 to 8 mg/l was noted. Nevertheless, sludge inoculation led to a net increase of the number of pathogenic bacteria...
September 14, 2016: Environmental Technology
Jun Zeng, Kai Lou, Cui-Jing Zhang, Jun-Tao Wang, Hang-Wei Hu, Ju-Pei Shen, Li-Mei Zhang, Li-Li Han, Tao Zhang, Qin Lin, Phillip M Chalk, Ji-Zheng He
Structural succession and its driving factors for nitrogen (N) cycling microbial communities during the early stages of soil development (0-44 years) were studied along a chronosequence in the glacial forelands of the Tianshan Mountain No.1 glacier in the arid and semi-arid region of central Asia. We assessed the abundance and population of functional genes affiliated with N-fixation (nifH), nitrification (bacterial and archaeal amoA), and denitrification (nirK/S and nosZ) in a glacier foreland using molecular methods...
2016: Frontiers in Microbiology
Jianbo Guo, Sihui Wang, Jing Lian, Huu Hao Ngo, Wenshan Guo, Yunman Liu, Yuanyuan Song
This study investigated the rapid start-up of the anaerobic ammonium oxidation (anammox) strategy by inoculating different biomass ratios of denitrifying granular sludge and anammox bacteria. The results demonstrated that two reactors (R1 and R2) were rapidly and successfully started-up on days 25 and 28, respectively, with nitrogen removal rates (NRRs) of 0.70kg/(m(3)·d) and 0.72kg/(m(3)·d) at biomass ratios of 10:1 (R1) and 50:1 (R2). The explanation for rapid start-up was found by examining the effect of five different sludge extracellular polymeric substances (EPS) on the activity of anammox bacteria in the batch experiments...
November 2016: Bioresource Technology
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