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Denitrifying bacteria

Jia Meng, Jiuling Li, Jianzheng Li, Philip Antwi, Kaiwen Deng, Jun Nan, Pianpian Xu
To enhance nutrient removal more cost-efficiently in microaerobic process treating piggery wastewater characterized by high ammonium (NH4(+)-N) and low chemical oxygen demand (COD) to total nitrogen (TN) ratio, a novel upflow microaerobic biofilm reactor (UMBR) was constructed and the efficiency in nutrient removal was evaluated with various influent COD/TN ratios and reflux ratios. The results showed that the biofilm on the carriers had increased the biomass in the UMBR and enhanced the enrichment of slow-growth-rate bacteria such as nitrifiers, denitrifiers and anammox bacteria...
November 11, 2017: Bioresource Technology
Zichao Wang, Pinghui Xia, Mengchun Gao, Kedong Ma, Zhiwei Deng, Junfeng Wei, Jing Zhang, Lin Wang, Guoxia Zheng, Yusuo Yang, Jinbo Chen, Yuejing Wang
The long-term effects of combined divalent copper (Cu(II)) and tetracycline (TC) on the performance, microbial activity and community in a sequencing batch reactor (SBR) were investigated. The addition of Cu(II), TC or mixed Cu(II)/TC caused the decrease of the organics and nitrogen removal efficiencies, and their decreased degrees were the lowest at the addition of mixed Cu(II)/TC. The increase of mixed Cu(II)/TC concentrations in the influent did not change the antagonistic effects between Cu(II) and TC on nitrifying and denitrifying activities...
November 6, 2017: Bioresource Technology
Jiamin Zhao, Chuanping Feng, Shuang Tong, Nan Chen, Shanshan Dong, Tong Peng, Shunlong Jin
The NO3(-) removal pathway and microorganisms change along with the height of an up-flow W-SPD bioreactor was investigated in this study. Modeling and microbial community analysis were used to analyze the denitrification behavior in W-SPD bioreactor. The results showed that NO3(-) removal rate matched for zero-order (R(2) > 0.97) and first-order (R(2) > 0.94) combination Michaelis-Menten kinetics, whereas microbial reaction rate suited for modified logistic model (R(2) > 0.99). The excellent denitrification performance (92...
November 6, 2017: Bioresource Technology
Inês C Santos, Misty S Martin, Michelle L Reyes, Doug D Carlton, Paula Stigler-Granados, Melissa A Valerio, Kristina W Whitworth, Zacariah L Hildenbrand, Kevin A Schug
Bacterial communities in groundwater are very important as they maintain a balanced biogeochemical environment. When subjected to stressful environments, for example, due to anthropogenic contamination, bacterial communities and their dynamics change. Studying the responses of the groundwater microbiome in the face of environmental changes can add to our growing knowledge of microbial ecology, which can be utilized for the development of novel bioremediation strategies. High-throughput and simpler techniques that allow the real-time study of different microbiomes and their dynamics are necessary, especially when examining larger data sets...
November 9, 2017: Science of the Total Environment
Yuexia Wu, Ligang Xu, Sai Wang, Zhenglu Wang, Jianying Shang, Xiqing Li, Chunmiao Zheng
This study investigated nitrate attenuation in low-permeability sediments (LPS) in a multi-layer aquifer by integrating hydrochemical, isotopic and microbiological molecular techniques in a field site. In the meantime, the overlying high-permeability sediment (HPS) was also examined on the nitrate attenuation for the sake of comparison. Additionally, laboratory flow-through experiments were conducted to assess the overall nitrate reduction rate in the two types of sediment. The δ(15)N-NO3(-) and δ(34)S-SO4(2-) values were more enriched by approximately 37‰ and 15‰ in the LPS than the overlying HPS associated with substantial reductions of the NO3(-) and SO4(2-) concentration, indicating the occurrence of strong bio-reductions in nitrate and sulfate...
November 7, 2017: Science of the Total Environment
Yun Wang, Hao Tian, Fei Huang, Wenmin Long, Qianpeng Zhang, Jing Wang, Ying Zhu, Xiaogang Wu, Guanzhou Chen, Liping Zhao, Lars R Bakken, Åsa Frostegård, Xiaojun Zhang
Quinoline is biodegradable under anaerobic conditions, but information about the degradation kinetics and the involved microorganisms is scarce. Here, the dynamics of a quinoline-degrading bacterial consortium were studied in anoxic batch cultures containing nitrate. The cultures removed 83.5% of the quinoline during the first 80 hours, which were dominated by denitrification, and then switched to methanogenesis when the nitrogen oxyanions were depleted. Time-resolved community analysis using pyrosequencing revealed that denitrifiying bacteria belonging to the genus Thauera were enriched during the denitrification stage from 12...
November 7, 2017: Scientific Reports
Zhixuan Yin, Li Xie, Qi Zhou, Xuejun Bi
This study investigated the simultaneous carbon and nitrogen removal from anaerobic effluent of cassava stillage using a lab-scale integrated system consisting of an upflow anaerobic sludge blanket (UASB) reactor and an activated sludge (AS) process. Simultaneous denitrification and methanogenesis (SDM) was observed in the UASB with nitrate recirculation. Compared with the blank reactor without recirculation, the overall chemical oxygen demand (COD) removal efficiencies in the combined system with nitrate recirculation were similar (80-90%), while the TN removal efficiencies were significantly improved from 4...
October 26, 2017: Journal of Bioscience and Bioengineering
G Kiran Kumar Reddy, Y V Nancharaiah
Biological removal of chromate [Cr(VI)] in the presence or absence of nitrate by granular sludge biofilms was investigated in batch experiments and in a sequencing batch reactor (SBR). Denitrifying granular sludge cultivated from activated sludge was able to directly reduce Cr(VI) in the presence of an electron donor. Bioreduction was dependent on the initial Cr(VI) and the granular sludge concentrations. Bioreduction of Cr(VI) was followed by Cr(III) precipitation or entrapment in the granular sludge which was corroborated with decrease in total soluble Cr and increase in inorganic content of biomass...
November 6, 2017: Environmental Science and Pollution Research International
Xiaojun Wang, Chengsong Ye, Zhaoji Zhang, Yan Guo, Ruili Yang, Shaohua Chen
To investigate the effects of temperature shock on N2O emissions, four treatments with rapidly changing incubation temperature from the control (20 °C) to 4, 12, 25, or 34 °C were conducted. Results showed that higher N2O emissions (0.023-0.37%) were observed when reactor contents received temperature shocks. N2O emissions increased as the temperature interval increased. Nitrate, nitrite, and nitrous oxide reduction rates generally followed the order: 34 °C > 25 °C > 20 °C > 12 °C > 4°C...
October 20, 2017: Bioresource Technology
Laura W Dijkhuizen, Paul Brouwer, Henk Bolhuis, Gert-Jan Reichart, Nils Koppers, Bruno Huettel, Anthony M Bolger, Fay-Wei Li, Shifeng Cheng, Xin Liu, Gane Ka-Shu Wong, Kathleen Pryer, Andreas Weber, Andrea Bräutigam, Henriette Schluepmann
Dinitrogen fixation by Nostoc azollae residing in specialized leaf pockets supports prolific growth of the floating fern Azolla filiculoides. To evaluate contributions by further microorganisms, the A. filiculoides microbiome and nitrogen metabolism in bacteria persistently associated with Azolla ferns were characterized. A metagenomic approach was taken complemented by detection of N2 O released and nitrogen isotope determinations of fern biomass. Ribosomal RNA genes in sequenced DNA of natural ferns, their enriched leaf pockets and water filtrate from the surrounding ditch established that bacteria of A...
October 30, 2017: New Phytologist
Octavio Perez-Garcia, Cody Mankelow, Kartik Chandran, Silas G Villas-Boas, Naresh Singhal
Metabolomics provides insights into the actual physiology of cells rather than their mere "potential", as provided by genomic and transcriptomic analysis. We investigate the modulation of nitrous oxide (N2O) accumulation by intracellular metabolites in denitrifying bacteria using metabolomics and genome-based metabolic network modeling. Profiles of metabolites and their rates of production/consumption were obtained for denitrifying batch cultures under four conditions: initial COD:N ratios of 11:1 and 4:1 with and without nitrite spiking (28 mg-N L(-1))...
November 16, 2017: Environmental Science & Technology
Linda Boss, Ramona Oehme, Susan Billig, Claudia Birkemeyer, Gunhild Layer
Heme d1 is a modified tetrapyrrole playing an important role for denitrification by acting as the catalytically essential cofactor in the cytochrome cd1 nitrite reductase of many denitrifying bacteria. In the course of heme d1 biosynthesis, the two propionate side chains on pyrrole rings A and B of the intermediate 12,18-didecarboxysiroheme are removed from the tetrapyrrole macrocycle. In the final heme d1 molecule, the propionate groups are replaced by two keto functions. Although it was speculated that the Radical SAM enzyme NirJ might be responsible for the removal of the propionate groups and introduction of the keto functions, this has not been shown experimentally, so far...
October 27, 2017: FEBS Journal
Georgios Giannopoulos, Matthew J Sullivan, Katherine Hartop, Gary Rowley, Andrew Gates, Nicholas J Watmough, D J Richardson
Bacterial denitrification is a respiratory process that is a major source and sink of the potent greenhouse gas nitrous oxide. Many denitrifying bacteria can adjust to life in both oxic and anoxic environments through differential expression of their respiromes in response to environmental signals such as oxygen, nitrate and nitric oxide. We used steady state oxic and anoxic chemostat cultures to demonstrate that the switch from aerobic to anaerobic metabolism is brought about by changes in the levels of expression of relatively few genes, but this is sufficient to adjust the configuration of the respirome to allow the organism to efficiently respire nitrate without the significant release of intermediates, such as nitrous oxide...
October 27, 2017: Environmental Microbiology
Swatantar Kumar, Martina Herrmann, Bo Thamdrup, Valérie F Schwab, Patricia Geesink, Susan E Trumbore, Kai-Uwe Totsche, Kirsten Küsel
Despite the high relevance of anaerobic ammonium oxidation (anammox) for nitrogen loss from marine systems, its relative importance compared to denitrification has less been studied in freshwater ecosystems, and our knowledge is especially scarce for groundwater. Surprisingly, phospholipid fatty acids (PLFA)-based studies identified zones with potentially active anammox bacteria within two superimposed pristine limestone aquifer assemblages of the Hainich Critical Zone Exploratory (CZE; Germany). We found anammox to contribute an estimated 83% to total nitrogen loss in suboxic groundwaters of these aquifer assemblages at rates of 3...
2017: Frontiers in Microbiology
Margarida M Santana, Juan M Gonzalez, Cristina Cruz
Many publications highlight the importance of nitric oxide (NO) in plant-bacteria interactions, either in the promotion of health and plant growth or in pathogenesis. However, the role of NO in the signaling between bacteria and plants and in the fate of their interaction, as well as the reconstruction of their interactive evolution, remains largely unknown. Despite the complexity of the evolution of life on Earth, we explore the hypothesis that denitrification and aerobic respiration were responsible for local NO accumulation, which triggered primordial antagonistic biotic interactions, namely the first phytopathogenic interactions...
2017: Frontiers in Microbiology
Fernando Torralbo, Sergio Menéndez, Iskander Barrena, José M Estavillo, Daniel Marino, Carmen González-Murua
Nitrous oxide (N2O) emissions have been increasing as a result of intensive nitrogen (N) fertilisation. Soil nitrification and denitrification are the main sources of N2O, and the use of ammonium-based fertilisers combined with nitrification inhibitors (NIs) could be useful in mitigating N2O emissions from agricultural systems. In this work we looked at the N2O mitigation capacity of two dimethylpyrazol-based NIs, 3,4-dimethylpyrazole phosphate (DMPP) and 2-(N-3,4-dimethyl-1H-pyrazol-1-yl) succinic acid isomeric mixture (DMPSA), on soil nitrifying and denitrifying microbial populations under two contrasting soil water contents (40% and 80% soil water filled pore space; WFPS)...
October 23, 2017: Scientific Reports
Haishu Sun, Feng Liu, Shengjun Xu, Shanghua Wu, Guoqiang Zhuang, Ye Deng, Jinshui Wu, Xuliang Zhuang
Removal of nitrogen (N) is a critical aspect in the functioning of constructed wetlands (CWs), and the N treatment in CWs depends largely on the presence and activity of macrophytes and microorganisms. However, the effects of plants on microorganisms responsible for N removal are poorly understood. In this study, a three-stage surface flow CW was constructed in a pilot-scale within monospecies stands of Myriophyllum aquaticum to treat swine wastewater. Steady-state conditions were achieved throughout the 600-day operating period, and a high (98...
2017: Frontiers in Microbiology
Antonio Castellano-Hinojosa, David Correa-Galeote, Presentación Carrillo, Eulogio J Bedmar, Juan M Medina-Sánchez
Wet deposition of reactive nitrogen (Nr) species is considered a main factor contributing to N inputs, of which nitrate ([Formula: see text]) is usually the major component in high-mountain lakes. The microbial group of denitrifiers are largely responsible for reduction of nitrate to molecular dinitrogen (N2) in terrestrial and aquatic ecosystems, but the role of denitrification in removal of contaminant nitrates in high-mountain lakes is not well understood. We have used the oligotrophic, high-altitude La Caldera lake in the Sierra Nevada range (Spain) as a model to study the role of denitrification in nitrate removal...
2017: Frontiers in Microbiology
Xiong Zheng, Juan Wang, Yinguang Chen, Yuanyuan Wei
Although the toxicity of silver nanoparticles (Ag NPs or nanosilver) to model bacteria has been reported, the effects of Ag NPs on microbial denitrification under anoxic conditions and the mechanism of Ag NPs induced-toxicity to denitrification remain unclear. In this study, the effects of Ag NPs on Paracoccus denitrificans under anoxic conditions were investigated, and the mechanism was explored by analyzing the transcriptional and proteomic responses of bacteria to Ag NPs. The presence of 5mg/L Ag NPs led to excessive nitrate accumulation (232...
October 16, 2017: Journal of Hazardous Materials
A M Ibekwe, A Gonzalez-Rubio, D L Suarez
The use of treated wastewater (TWW) for irrigation has been suggested as an alternative to use of fresh water because of the increasing scarcity of fresh water in arid and semiarid regions of the world. However, significant barriers exist to widespread adoption due to some potential contaminants that may have adverse effects on soil quality and or public health. In this study, we investigated the abundance and diversity of bacterial communities and the presence of potential pathogenic bacterial sequences in TWW in comparison to synthetic fresh water (SFW) using pyrosequencing...
October 17, 2017: Science of the Total Environment
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