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Nitrate reducing bacteria

Hao-Yi Cheng, Xia-Di Tian, Chuanhao Li, Shusen Wang, Shi-Gang Su, Hong-Cheng Wang, Bo Zhang, Hafiz Muhammad Adeel Sharif, Aijie Wang
Biological removal of nitrate, a highly-concerning contaminant, is limited when the aqueous environment lacks bioavailable electron donors. In this study, we demonstrated, for the first time, that bacteria can directly use the electrons originated from photoelectrochemical process to carry out the denitrification. In such photoelectrotrophic denitrification (PEDeN) systems (denitrification biocathode coupling with TiO2 photoanode), nitrogen removal was verified solely relying on the illumination dosing without consuming additional chemical reductant or electric power...
October 13, 2017: Environmental Science & Technology
Xavier F Hospital, Eva Hierro, Jacint Arnau, José Carballo, Juan S Aguirre, Marta Gratacós-Cubarsí, Manuela Fernández
The effect of nitrate and the combination of nitrate/nitrite on Listeria innocua (as surrogate of Listeria monocytogenes). And two selected spoilage microorganisms (Proteus vulgaris and Serratia liquefaciens) was studied in dry-cured ham. Hams were manufactured with different concentrations of curing agents: KNO3 (600 and 150mg/kg) alone or in combination with NaNO2 (600 and 150mg/kg). The addition of 500mg/kg of sodium ascorbate was also evaluated in a batch with 600mg/kg of nitrate and nitrite. The target microorganisms were inoculated by injection in semimembranosus, biceps femoris and in the shank, prior to curing...
November 2017: Food Research International
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
Malin Bomberg, Jarno Mäkinen, Marja Salo, Mona Arnold
Sulfate-rich mine water must be treated before it is released into natural water bodies. We tested ethanol as substrate in bioreactors designed for biological sulfate removal from mine water containing up to 9 g L(-1) sulfate, using granular sludge from an industrial waste water treatment plant as inoculum. The pH, redox potential, and sulfate and sulfide concentrations were measured twice a week over a maximum of 171 days. The microbial communities in the bioreactors were characterized by qPCR and high throughput amplicon sequencing...
September 20, 2017: Microorganisms
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
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
Gloria N Okpala, Chuan Chen, Tekle Fida, Gerrit Voordouw
Oil fields can experience souring, the reduction of sulfate to sulfide by sulfate-reducing microorganisms. At the Terra Nova oil field near Canada's east coast, with a reservoir temperature of 95°C, souring was indicated by increased hydrogen sulfide in produced waters (PW). Microbial community analysis by 16S rRNA gene sequencing showed the hyperthermophilic sulfate-reducing archaeon Archaeoglobus in Terra Nova PWs. Growth enrichments in sulfate-containing media at 55-70°C with lactate or volatile fatty acids yielded the thermophilic sulfate-reducing bacterium (SRB) Desulfotomaculum...
2017: Frontiers in 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...
November 15, 2017: Water Research
Shaomei He, Roman A Barco, David Emerson, Eric E Roden
Extracellular electron transfer (EET) is recognized as a key biochemical process in circumneutral pH Fe(II)-oxidizing bacteria (FeOB). In this study, we searched for candidate EET genes in 73 neutrophilic FeOB genomes, among which 43 genomes are complete or close-to-complete and the rest have estimated genome completeness ranging from 5 to 91%. These neutrophilic FeOB span members of the microaerophilic, anaerobic phototrophic, and anaerobic nitrate-reducing FeOB groups. We found that many microaerophilic and several anaerobic FeOB possess homologs of Cyc2, an outer membrane cytochrome c originally identified in Acidithiobacillus ferrooxidans...
2017: Frontiers in Microbiology
Abdoulaye Thioye, Zouhaier Ben Ali Gam, Malick Mbengue, Jean-Luc Cayol, Manon Joseph-Bartoli, Coumba Touré-Kane, Marc Labat
Several strains of sulfate-reducing bacteria were isolated from marine sediments recovered from Hann Bay (Senegal). All were related to members of the genus Desulfovibrio. A strictly anaerobic, mesophilic and moderately halophilic strain designated BLaC1T was further characterized. Cells of strain BLaC1T stained Gram-negative and were 0.5 µm wide and 2-4 µm long, motile, rod-shaped and non-spore-forming. The four major fatty acids were anteiso-C15 : 0, iso-C15 : 0, iso-C17 : 0 and anteiso-C17 : 0...
September 2017: International Journal of Systematic and Evolutionary Microbiology
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...
October 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
Sunita J Varjani, Edgard Gnansounou
Petroleum is produced by thermal decay of buried organic material over millions of years. Petroleum oilfield ecosystems represent resource of reduced carbon which favours microbial growth. Therefore, it is obvious that many microorganisms have adapted to harsh environmental conditions of these ecosystems specifically temperature, oxygen availability and pressure. Knowledge of microorganisms present in ecosystems of petroleum oil reservoirs; their physiological and biological properties help in successful exploration of petroleum...
August 9, 2017: Bioresource Technology
Sophie-Marie Martirani-Von Abercron, Patricia Marín, Marta Solsona-Ferraz, Mayra-Alejandra Castañeda-Cataña, Silvia Marqués
Toxic polycyclic aromatic hydrocarbons (PAHs) are frequently released into the environment from anthropogenic sources. PAH remediation strategies focus on biological processes mediated by bacteria. The availability of oxygen in polluted environments is often limited or absent, and only bacteria able to thrive in these conditions can be considered for bioremediation strategies. To identify bacterial strains able to degrade PAHs under oxygen-limiting conditions, we set up enrichment cultures from samples of an oil-polluted aquifer, using either anoxic or microaerophilic condition and with PAHs as the sole carbon source...
August 25, 2017: Microbial Biotechnology
Wessam Galia, Francoise Leriche, Stéphane Cruveiller, Cindy Garnier, Vincent Navratil, Audrey Dubost, Stéphanie Blanquet-Diot, Delphine Thevenot-Sergentet
BACKGROUND: Enterohemorrhagic Escherichia coli (EHEC) are zoonotic agents associated with outbreaks worldwide. Growth of EHEC strains in ground beef could be inhibited by background microbiota that is present initially at levels greater than that of the pathogen E. coli. However, how the microbiota outcompetes the pathogenic bacteria is unknown. Our objective was to identify metabolic pathways of EHEC that were altered by natural microbiota in order to improve our understanding of the mechanisms controlling the growth and survival of EHECs in ground beef...
August 3, 2017: BMC Genomics
Chao Wei, Wenjie He, Li Wei, Jun Ma, Chunying Li
The biodegradation-electron transfer with sulfur metabolism integrated (BESI(®)) process was used for the treatment of real flue gas desulfurization wastewater. The BESI(®) process consists of an anaerobic activated sludge reactor, an anoxic activated sludge reactor, and an aerobic bio-film reactor. The performance of the integrated process was evaluated by the removal efficiencies of organics and nitrogen pollutants. The sulfate in the wastewater was used as an abundant sulfur source to drive the integrated process...
July 22, 2017: Bioprocess and Biosystems Engineering
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
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
Casper Thorup, Andreas Schramm, Alyssa J Findlay, Kai W Finster, Lars Schreiber
This study demonstrates that the deltaproteobacterium Desulfurivibrio alkaliphilus can grow chemolithotrophically by coupling sulfide oxidation to the dissimilatory reduction of nitrate and nitrite to ammonium. Key genes of known sulfide oxidation pathways are absent from the genome of D. alkaliphilus Instead, the genome contains all of the genes necessary for sulfate reduction, including a gene for a reductive-type dissimilatory bisulfite reductase (DSR). Despite this, growth by sulfate reduction was not observed...
July 18, 2017: MBio
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