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Denitrifying bacteria

Zhongchen Yang, Luhua Yang, Caijie Wei, Weizhong Wu, Xufei Zhao, Ting Lu
In this study, the performances of nitrogen removal in constructed wetlands using solid carbon source with limited aeration were investigated. The blends of poly-3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV) and polyacetic acid (PLA) were used as the carbon source and biofilm support. The performances of nitrogen removal, microbial abundance and microbial community structure in the biofilm attached on PHBV/PLA were investigated. Higher ammonia removal efficiency (91.00%) and total nitrogen removal efficiency (97...
August 4, 2017: Bioresource Technology
Markus Warnke, Christian Jacoby, Tobias Jung, Michael Agne, Mario Mergelsberg, Robert Starke, Nico Jehmlich, Martin von Bergen, Hans-Hermann Richnow, Thomas Brüls, Matthias Boll
The denitrifying Betaproteobacterium Sterolibacterium denitrificans serves as model organism for studying the oxygen-independent degradation of cholesterol. Here, we demonstrate its capability of degrading various globally abundant side chain containing zoo-, phyto- and mycosterols. We provide the complete genome which empowered an integrated genomics/proteomics/metabolomics approach, accompanied by the characterization of a characteristic enzyme of steroid side chain degradation. The results indicate that individual molybdopterin-containing steroid dehydrogenases are involved in C25-hydroxylations of steroids with different isoprenoid side chains, followed by the unusual conversion to C26-oic acids...
September 21, 2017: Environmental Microbiology
Ann Arfken, Bongkeun Song, Jeff S Bowman, Michael Piehler
The eastern oyster (Crassostrea virginica) is a foundation species providing significant ecosystem services. However, the roles of oyster microbiomes have not been integrated into any of the services, particularly nitrogen removal through denitrification. We investigated the composition and denitrification potential of oyster microbiomes with an approach that combined 16S rRNA gene analysis, metabolic inference, qPCR of the nitrous oxide reductase gene (nosZ), and N2 flux measurements. Microbiomes of the oyster digestive gland, the oyster shell, and sediments adjacent to the oyster reef were examined based on next generation sequencing (NGS) of 16S rRNA gene amplicons...
2017: PloS One
Guanhong Chen, Zhirong Zhang, Zhiyuan Zhang, Renduo Zhang
The aim of this study was to investigate the role of redox-active components of biochar in the denitrification processes and N2O reduction. Both biochars pyrolyzed at 300 and 800°C were separated into two redox-active components (i.e., dissolved aromatic moieties and condensed aromatic structure), then applied to study the reduction process of denitrifying bacteria from a paddy soil. Results demonstrated three main pathways of the biochar redox-active components for the denitrification processes and N2O reduction...
September 17, 2017: Science of the Total Environment
Eveline M van den Berg, Marina P Elisário, J Gijs Kuenen, Robbert Kleerebezem, Mark C M van Loosdrecht
Denitrification and dissimilatory reduction to ammonium (DNRA) are competing nitrate-reduction processes that entail important biogeochemical consequences for nitrogen retention/removal in natural and man-made ecosystems. The nature of the available carbon source and electron donor have been suggested to play an important role on the outcome of this microbial competition. In this study, the influence of lactate as fermentable carbon source on the competition for nitrate was investigated for varying ratios of lactate and nitrate in the influent (Lac/N ratio)...
2017: Frontiers in Microbiology
Elizabeth G Wilbanks, Verena Salman-Carvalho, Ulrike Jaekel, Parris T Humphrey, Jonathan A Eisen, Daniel H Buckley, Stephen H Zinder
Microbial interactions driving key biogeochemical fluxes often occur within multispecies consortia that form spatially heterogeneous microenvironments. Here, we describe the "green berry" consortia of the Sippewissett salt marsh (Falmouth, MA, United States): millimeter-sized aggregates dominated by an uncultured, diazotrophic unicellular cyanobacterium of the order Chroococcales (termed GB-CYN1). We show that GB-CYN1 is closely related to Crocosphaera watsonii (UCYN-B) and "Candidatus Atelocyanobacterium thalassa" (UCYN-A), two groups of unicellular diazotrophic cyanobacteria that play an important role in marine primary production...
2017: Frontiers in Microbiology
Elena Hernández-Del Amo, Anna Menció, Frederic Gich, Josep Mas-Pla, Lluís Bañeras
Natural attenuation processes alleviate the impact of fertilization practices on groundwater resources. Therefore, identifying the occurrence of denitrification has become a requirement for water quality management. Several approaches are useful for this purpose, such as isotopic and microbiological methods, each of them providing distinct but complementary information about denitrification reactions, attenuation rates and their occurrence in the aquifer. In this paper, we investigate the contribution of both approaches to describe denitrification in a consolidated rock aquifer (limestone and marls), with a porosity related to fracture networks located in the northeastern sector of the Osona basin (NE Spain)...
September 16, 2017: Science of the Total Environment
Wenda Huang, Jingjing Guo, Ran Tao, Ying Man, Yunv Dai, Yang Yang
Efficient isolation of target DNA is a crucial first step of DNA-based metagenomic analyses of environmental samples. Insufficient quantity and purity of DNA isolated using commercial kits result in missing genetic information, especially for large-diameter substrates in constructed wetlands (CWs). Here, we addressed this problem by devising a cost-effective calcium chloride lysozyme-sodium dodecyl sulfate (SDS) method (CCLS), with key improvements in the steps of humic acid removal and cell lysis. The buffer comprising Tris, EDTA, Na2O2P7 and PVPP (TENP), and skim milk, could reduce adsorption between microorganisms and substrates, and calcium chloride precipitated and removed over 94% of humic acid...
September 16, 2017: Applied Microbiology and Biotechnology
Santosh Kumar, Stephen Spiro
The genome of the denitrifying bacterium Paracoccus denitrificans predicts the expression of a small heme-containing nitric oxide (NO) binding protein, H-NOX. The genome organization and prior work in other bacteria suggest that H-NOX interacts with a diguanylate cyclase that cyclizes GTP to make cyclic di-GMP (cdGMP). Since cdGMP frequently regulates attached growth as a biofilm, we first established conditions for biofilm development by P. denitrificans. We found that adhesion to a polystyrene surface is strongly stimulated by the addition of 10 mM Ca(2+) to rich media...
September 2017: MSphere
Wanlin Lyu, Lei Huang, Guangquan Xiao, Yucheng Chen
A set of constructed wetlands under two different carbon sources, namely, glucose (CW) and sodium acetate (YW), was established at a laboratory scale with influent COD/N ratios of 20:1, 10:1, 7:1, 4:1, and 0 to analyze the influence of carbon supply on nitrous oxide emissions. Results showed that the glucose systems generated higher N2O emissions than those of the sodium acetate systems. The higher amount of N2O-releasing fluxes in the CWs than in the YWs was consistent with the higher NO2(-)-N accumulation in the former than in the latter...
August 13, 2017: Bioresource Technology
Jessica A Lee, Christopher A Francis
Denitrification is a dominant nitrogen loss process in the sediments of San Francisco Bay. In this study, we sought to understand the ecology of denitrifying bacteria by using next-generation sequencing (NGS) to survey the diversity of a denitrification functional gene, nirS (encoding cytchrome-cd1 nitrite reductase), along the salinity gradient of San Francisco Bay over the course of a year. We compared our dataset to a library of nirS sequences obtained previously from the same samples by standard PCR cloning and Sanger sequencing, and showed that both methods similarly demonstrated geography, salinity, and, to a lesser extent, nitrogen, to be strong determinants of community composition...
September 11, 2017: Environmental Microbiology
Yan Zhang, Mei Yu, Jianhua Guo, Di Wu, Zheng-Shuang Hua, Guang-Hao Chen, Hui Lu
Denitrifying sulfur conversion-assisted enhanced biological phosphorus removal (DS-EBPR) has recently been developed for simultaneously removing nitrogen and phosphorus from saline sewage with minimal sludge production. This novel process could potentially enable sustainable wastewater treatment. Yet, the core functional bacteria and their roles are unknown. Here, we used high-throughput 16S rRNA gene sequencing coupled with principal coordinates analysis and ANOVA with Tukey's test to unravel the spatiotemporal heterogeneity of functional bacteria and their synergetic and competitive interactions...
September 7, 2017: Scientific Reports
Aura Ontiveros-Valencia, Chen Zhou, Zehra Esra Ilhan, Louis Cornette de Saint Cyr, Rosa Krajmalnik-Brown, Bruce E Rittmann
Molecular microbiology tools (i.e., 16S rDNA gene sequencing) were employed to elucidate changes in the microbial community structure according to the total electron acceptor loading (controlled by influent flow rate and/or medium composition) in a H2-based membrane biofilm reactor evaluated for removal of hexavalent uranium. Once nitrate, sulfate, and dissolved oxygen were replaced by U(VI) and bicarbonate and the total acceptor loading was lowered, slow-growing bacteria capable of reducing U(VI) to U(IV) dominated in the biofilm community: Replacing denitrifying bacteria Rhodocyclales and Burkholderiales were spore-producing Clostridiales and Natranaerobiales...
August 29, 2017: Water Research
Rui Tao, Steven A Wakelin, Yongchao Liang, Baowei Hu, Guixin Chu
The effects of consecutive application of chemical fertilizer with or without organic fertilizer on soil N2O emissions and denitrifying community structure in a drip-irrigated field were determined. The four fertilizer treatments were (i) unfertilized, (ii) chemical fertilizer, (iii) 60% chemical fertilizer plus cattle manure, and (iv) 60% chemical fertilizer plus biofertilizer. The treatments with organic amendments (i.e. cattle manure and biofertilizer) reduced cumulative N2O emissions by 4.9-9.9%, reduced the N2O emission factor by 1...
August 31, 2017: Science of the Total Environment
Xu Yan, Jiaxi Zheng, Yunping Han, Jianwei Liu, Jianhui Sun
The problem of producing strong greenhouse gas of nitrous oxide (N2O) from biological nitrogen removal (BNR) process in wastewater treatment plants (WWTP) has elicited great concern from various sectors. In this study, three laboratory-scale wastewater treatment systems, with influent C/N ratios of 3.4, 5.4, and 7.5, were set up to study the effect of influent C/N ratio on N2O generation in anaerobic/anoxic/oxic (A(2)O) process. Results showed, with the increased influent C/N ratio, N2O generation from both nitrification and denitrification process was decreased, and the N2O-N conversion ratio of the process was obviously reduced from 2...
September 1, 2017: Environmental Science and Pollution Research International
Pengyi Lv, Jinxue Luo, Xuliang Zhuang, Dongqing Zhang, Zhanbin Huang, Zhihui Bai
Aerobic denitrification is a process reducing the nitrate into gaseous nitrogen forms in the presence of oxygen gas, which makes the nitrification and denitrification performed simultaneously. However, little was known on the diversity of the culturable aerobic denitrifying bacteria in the surface water system. In this study, 116 strains of aerobic denitrifying bacteria were isolated from the sediment, water and biofilm samples in Liangshui River of Beijing. These bacteria were classified into 14 genera based on the 16 S rDNA, such as Pseudomonas, Rheinheimera, and Gemmobacter...
August 30, 2017: Scientific Reports
Qiang Kong, Xiao He, Shuai-Shuai Ma, Yu Feng, Ming-Sheng Miao, Yuan-da Du, Fei Xu, Qian Wang
The performance and microbial community changes of an activated sludge sequencing batch reactor were evaluated after exposure to trimethoprim for 51days. The average chemical oxygen demand, ammonia nitrogen, phosphorus efficiencies were 88.6%±0.56%, 90.47%±0.29% and 64.25%±1.12%, respectively. The protein and polysaccharide contents increased with increasing trimethoprim concentration to protect the cells from the unfavorable conditions. The chemical composition of extracellular polymeric substances increased...
November 2017: Bioresource Technology
Qianwen Sui, Chao Jiang, Dawei Yu, Meixue Chen, Junya Zhang, Yawei Wang, Yuansong Wei
Due to high-strength of organic matters, nutrients and pathogen, swine wastewater is a major source of pollution to rural environment and surface water. A sequencing-batch membrane bioreactor (SMBR) system with an automatic control strategy was developed for high-strength swine wastewater treatment. Short-cut nitrification and denitrification (SND) was achieved at nitrite accumulation rate of 83.6%, with removal rates of COD, NH4(+)-N and TN at 95%, 99% and 93%, respectively, at reduced HRT of 6.0 d and TN loading rate of 0...
May 8, 2017: Journal of Hazardous Materials
Sara Hallin, Laurent Philippot, Frank E Löffler, Robert A Sanford, Christopher M Jones
Microorganisms with the capacity to reduce the greenhouse gas nitrous oxide (N2O) to harmless dinitrogen gas are receiving increased attention due to increasing N2O emissions (and our need to mitigate climate change) and to recent discoveries of novel N2O-reducing bacteria and archaea. The diversity of denitrifying and nondenitrifying microorganisms with capacity for N2O reduction was recently shown to be greater than previously expected. A formerly overlooked group (clade II) in the environment include a large fraction of nondenitrifying N2O reducers, which could be N2O sinks without major contribution to N2O formation...
August 10, 2017: Trends in Microbiology
Honglei Wang, Na Deng, Duoyang Wu, Shu Hu
A comprehensive understanding of how microbial associated with nitrogen (N) cycling respond to artificial vegetation restoration is still lacking, particularly in arid to semi-arid degraded ecosystems. We compared soil net N mineralization rates and the abundance of bacteria, archaea, and eleven N microbial genes on the northern Loess Plateau of China during the process of artificial vegetation restoration. The quantitative relationships between net N mineralization rates and N microbial genes were determined...
August 10, 2017: Scientific Reports
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