The objectives of this study were (i) to isolate and characterize of cultivable denitrifying bacteria using classic microbiological and molecular methods, (ii) to compare of 16S rRNA and nosZ genes as molecular markers, (iii) to determine bacterial community structure and diversity in soil samples using single-strand conformation polymorphism (SSCP) analysis. In this study, 49 bacterial isolates were cultivated and phylogenetic analyses grouped them into two phyla: Proteobacteria (37 species) and Firmicutes (12 species). Our study showed that the nosZ functional gen could be used to identify denitrifying bacteria abundance in environment but could not be used to identify pure bacterial cultures. In addition, the bacterial community structure showed significant differences among the various soil types. Phylogenetic analysis of community structure indicated that 51 clones could be divided into 2 phylotypes. Uncultured bacteria (80.4%) and Gammaproteobacteria (19.6%) were the dominant components of the soil bacterial community. For 16S rRNA, PCR products of 49 bacteria were obtained with 27F-1492R primer pairs. For nosZ, PCR products were obtained with primers 1F-1R (259 bp), 2F-2R (267 bp), and F-1622R (453 bp) of 39 bacteria that the single nosZ band provided on the agarose gel. The bacterial 16S rRNA gene clone library was dominated by Gammaproteobacteria and Bacilli. The nosZ clone sequences did not represent the bacteria from which they were obtained but were found to be closer to the environmental clones. Our study showed that the nosZ functional gene could be used to identify denitrification abundance in environment but could not be used to identify pure bacterial cultures. It was also found that the nosZ sequences showed uncultured denitrifier species.
- MeSH
- Bacillus klasifikace izolace a purifikace MeSH
- Bacteria klasifikace izolace a purifikace MeSH
- bakteriální geny MeSH
- denitrifikace * MeSH
- DNA bakterií genetika MeSH
- fylogeneze MeSH
- Gammaproteobacteria klasifikace izolace a purifikace MeSH
- mikrobiota * MeSH
- polymorfismus délky restrikčních fragmentů MeSH
- půdní mikrobiologie * MeSH
- RNA ribozomální 16S genetika MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
Trichodesmium is an important dinitrogen (N2)-fixing cyanobacterium in marine ecosystems. Recent nucleic acid analyses indicate that Trichodesmium colonies with their diverse epibionts support various nitrogen (N) transformations beyond N2 fixation. However, rates of these transformations and concentration gradients of N compounds in Trichodesmium colonies remain largely unresolved. We combined isotope-tracer incubations, micro-profiling and numeric modelling to explore carbon fixation, N cycling processes as well as oxygen, ammonium and nitrate concentration gradients in individual field-sampled Trichodesmium colonies. Colonies were net-autotrophic, with carbon and N2 fixation occurring mostly during the day. Ten percent of the fixed N was released as ammonium after 12-h incubations. Nitrification was not detectable but nitrate consumption was high when nitrate was added. The consumed nitrate was partly reduced to ammonium, while denitrification was insignificant. Thus, the potential N transformation network was characterised by fixed N gain and recycling processes rather than denitrification. Oxygen concentrations within colonies were ~60-200% air-saturation. Moreover, our modelling predicted steep concentration gradients, with up to 6-fold higher ammonium concentrations, and nitrate depletion in the colony centre compared to the ambient seawater. These gradients created a chemically heterogeneous microenvironment, presumably facilitating diverse microbial metabolisms in millimetre-sized Trichodesmium colonies.
- MeSH
- amoniové sloučeniny metabolismus MeSH
- autotrofní procesy MeSH
- denitrifikace MeSH
- dusičnany metabolismus MeSH
- dusík metabolismus MeSH
- fixace dusíku MeSH
- koloběh dusíku MeSH
- koloběh uhlíku MeSH
- kyslík metabolismus MeSH
- mořská voda mikrobiologie MeSH
- nitrifikace MeSH
- oxid uhličitý metabolismus MeSH
- Trichodesmium metabolismus MeSH
- uhlík metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
Denitrifying woodchip bioreactors, natural treatment systems used for the reduction of nitrates in agricultural runoff or groundwater, may cause adverse side effects within receiving waters. One of the least studied but nonetheless still serious issues is the production of hydrogen sulphide, which occurs in bioreactors under operating conditions favourable to its creation. The aim of this paper is to elucidate the effect of process parameters on the production of sulphides and the proportion of hydrogen sulphide in a 1-year-long experimental study with four laboratory-scale denitrifying bioreactors. During the study, the strong dependence of sulphate reduction and the production of sulphides on the effluent oxidation-reduction potential (ORP) and nitrate-nitrogen (NO3-N) concentrations of bioreactors became evident. Sulphide formation occurred at concurrent effluent NO3-N concentrations below 3 mg/L and ORPs lower than - 100 mV. The tested hydraulic retention time of 1.7 days was sufficiently long to achieve these conditions. At an effluent pH of 7 or lower, the majority of the total sulphides present were in the form of hydrogen sulphide. It is suggested that in order to avoid the production of hydrogen sulphide, the production of total sulphides has to be minimised.
- MeSH
- bioreaktory MeSH
- denitrifikace * MeSH
- dusičnany MeSH
- dusík * MeSH
- sulfidy MeSH
- Publikační typ
- časopisecké články MeSH
A systematic study on the lack of dissimilatory nitrate reductase (NAR) properties in Halomonas strains had been reported so far. The effects of different factors on Halomonas sp. B01 NAR activity were investigated. The salt tolerance of NAR was characterized. The denitrification process under high salt conditions was reported. Halomonas sp. B01 expressed membrane-bound NAR under induced culture by nitrate. The optimum pH of the enzyme reaction system was 8, and the optimum temperature was 30 °C. The mRNA expression abundance of narH in NAR encoding gene was highest in the 60 g/L NaCl inducing matrix. The NaCl concentration of optimum growth and induction of NAR were both 60 g/L. The ectoine added to the NAR vitro enzyme reaction system could maintain NAR activity under high NaCl concentration. In the range of 0-60 g/L NaCl, the NAR activity was stable at 17.7 (± 0.3) U/mg. The denitrification was performed by Halomonas sp. B01 at 60 g/L NaCl, and the denitrification rate reached 97.1% at 24 h. This study reveals for the first time the NAR properties of Halomonas strains, which provides a theoretical and technical basis for the nitrogen removal of high-salt nitrogenous wastewater using this strain.
- MeSH
- aminokyseliny diaminové metabolismus MeSH
- bakteriální proteiny genetika metabolismus MeSH
- buněčná membrána metabolismus MeSH
- chlorid sodný metabolismus MeSH
- denitrifikace MeSH
- dusičnany metabolismus MeSH
- Halomonas enzymologie genetika růst a vývoj metabolismus MeSH
- koncentrace vodíkových iontů MeSH
- nitrátreduktasa genetika metabolismus MeSH
- regulace genové exprese u bakterií MeSH
- teplota MeSH
- tolerance k soli * MeSH
- Publikační typ
- časopisecké články MeSH
Tropical rainforest soils harbor a considerable diversity of soil fauna that contributes to emissions of N2O. Despite their ecological dominance, there is limited information available about the contribution of epigeal ant mounds to N2O emissions in these tropical soils. This study aimed to determine whether ant mounds contribute to local soil N emissions in the tropical humid rainforest. N2O emission was determined in vitro from individual live ants, ant-processed mound soils, and surrounding reference soils for two trophically distinct and abundant ant species: the leaf-cutting Atta mexicana and omnivorous Solenopsis geminata. The abundance of total bacteria, nitrifiers (AOA and AOB), and denitrifiers (nirK, nirS, and nosZ) was estimated in these soils using quantitative PCR, and their respective mineral N contents determined. There was negligible N2O emission detected from live ant individuals. However, the mound soils of both species emitted significantly greater (3-fold) amount of N2O than their respective surrounding reference soils. This emission increased significantly up to 6-fold in the presence of acetylene, indicating that, in addition to N2O, dinitrogen (N2) is also produced from these mound soils at an equivalent rate (N2O/N2 = 0.57). Functional gene abundance (nitrifiers and denitrifiers) and mineral N pools (ammonium and nitrate) were significantly greater in mound soils than in their respective reference soils. Furthermore, in the light of the measured parameters and their correlation trends, nitrification and denitrification appeared to represent the major N2O-producing microbial processes in ant mound soils. The ant mounds were estimated to contribute from 0.1 to 3.7% of the total N2O emissions of tropical rainforest soils.
- MeSH
- Bacteria genetika metabolismus MeSH
- bakteriální geny MeSH
- denitrifikace genetika MeSH
- deštný prales MeSH
- Formicidae metabolismus mikrobiologie MeSH
- nitrifikace genetika MeSH
- oxid dusný analýza metabolismus MeSH
- půda chemie MeSH
- půdní mikrobiologie * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The adaptation of Anammox (ANaerobic AMMonium OXidation) to low temperatures (10-15°C) is crucial for sustaining energy-efficient nitrogen removal from the mainstream of municipal wastewater. But, current adaptation methods take months or even years. To speed up the adaption of Anammox to low temperatures, this study describes a new approach: exposing Anammox microorganisms to an abrupt temporary reduction of temperature, i.e., cold shock. Anammox biomass in a moving bed biofilm reactor was subjected to three consecutive cold shocks (reduction from 24 ± 2 to 5.0 ± 0.2°C), each taking eight hours. Before the cold shocks, Anammox activity determined in ex situ tests using the temperature range of 12.5-19.5°C was 0.005-0.015 kg-N kg-VSS-1 day-1 . Cold shocks increased the activity of Anammox at 10°C to 0.054 kg-N kg-VSS-1 day-1 after the third shock, which is similar to the highest activities obtained for cold-enriched or adapted Anammox reported in the literature (0.080 kg-N kg-VSS-1 day-1 ). Fluorescence in situ hybridization analysis showed that Ca. Brocadia fulgida was the dominant species. Thus, cold shocks are an intriguing new strategy for the adaptation of Anammox to low temperature. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:277-281, 2018.
- MeSH
- amoniové sloučeniny chemie MeSH
- anaerobióza genetika MeSH
- Bacteria genetika růst a vývoj metabolismus MeSH
- biofilmy růst a vývoj MeSH
- bioreaktory MeSH
- čištění vody metody MeSH
- denitrifikace genetika MeSH
- dusík metabolismus MeSH
- hybridizace in situ fluorescenční MeSH
- nízká teplota MeSH
- odpad tekutý - odstraňování metody MeSH
- oxidace-redukce MeSH
- reakce na chladový šok genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Nitrogen leaching owing to elevated acid deposition remains the main ecosystem threat worldwide. We aimed to contribute to the understanding of the highly variable nitrate losses observed in Europe after acid deposition retreat. Our study proceeded in adjacent beech and spruce forests undergoing acidification recovery and differing in nitrate leaching. We reconstructed soil microbial functional characteristics connected with nitrogen and carbon cycling based on community composition. Our results showed that in the more acidic spruce soil with high carbon content, where Acidobacteria and Actinobacteria were abundant (Proteo:Acido = 1.3), the potential for nitrate reduction and loss via denitrification was high (denitrification: dissimilative nitrogen reduction to ammonium (DNRA) = 3). In the less acidic beech stand with low carbon content, but high nitrogen availability, Proteobacteria were more abundant (Proteo:Acido = 1.6). Proportionally less nitrate could be denitrified there (denitrification:DNRA = 1), possibly increasing its availability. Among 10 potential keystone species, microbes capable of DNRA were identified in the beech soil while instead denitrifiers dominated in the spruce soil. In spite of the former acid deposition impact, distinct microbial functional guilds developed under different vegetational dominance, resulting in different N immobilization potentials, possibly influencing the ecosystem's nitrogen retention ability.
- MeSH
- Bacteria klasifikace metabolismus MeSH
- buk (rod) růst a vývoj MeSH
- denitrifikace * MeSH
- dusičnany analýza MeSH
- koncentrace vodíkových iontů MeSH
- mikrobiota * MeSH
- půda chemie MeSH
- půdní mikrobiologie * MeSH
- smrk růst a vývoj MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Evropa MeSH
In this study a completely stirred tank reactor was used to study the effect of sulfide to nitrate (S/N) ratio on sulfide removal while nitrate was used as electron acceptor. Several S/N ratios were studied for this purpose ranging from 0.3 to 2.4 mol/mol. The complete sulfide removal was achieved when S/N ratio 0.85 mol/mol was used with the autotrophic denitrification efficiency up to 80 %. No nitrite accumulation was observed, and the main product of sulfide oxidation was sulfate. Dissimilatory nitrogen reduction to ammonia occurred and subsequently, elemental sulfur accumulated while S/N ratio was higher than 1.3 mol/mol. The specific autotrophic denitrification rates under S/N ratios 0.8 and 1.2 were 5 and 26 mg g(-1) h(-1) (N-NO3 (-), VSS), respectively. Thiobacillus denitrificans and Thiomicrospira denitrificans were detected in the reactor by fluorescent in situ hybridization, but their overall representation was not more than 5 % of the entire microbial populations.
- MeSH
- amoniak metabolismus MeSH
- bioreaktory mikrobiologie MeSH
- denitrifikace * MeSH
- dusičnany metabolismus MeSH
- dusík analýza MeSH
- Epsilonproteobacteria genetika izolace a purifikace metabolismus MeSH
- hybridizace in situ fluorescenční MeSH
- oxidace-redukce MeSH
- síra analýza MeSH
- sírany metabolismus MeSH
- sulfidy metabolismus MeSH
- Thiobacillus genetika izolace a purifikace metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Nitrate is commonly found in the influent of subsurface-batch constructed wetlands (SSB CWs) used for tertiary wastewater treatments. To understand the effects of plants and the litter on nitrate removal, as well as on nitrogen transformation in SSB CWs, six laboratory-scale SSB CW microcosms were set up in duplicate and were operated as batch systems with hydraulic residence time (HRT) of 5d. The presence of Typha latifolia enhanced nitrate removal in SSB CWs, and the N removed by plant uptake was mainly stored in aboveground biomass. Typha litter addition greatly improved nitrate removal in SSB CWs through continuous input of labile organic carbon, and calculated enrichment factors (ε) were between -12.1‰--13.9‰ from the nitrogen stable isotope analysis, suggesting that denitrification plays a dominant role in the N removal. Most significantly, simultaneous sulfur-based autotrophic and heterotrophic denitrification was observed in CWs. Finally, mass balance showed that denitrification, sedimentation burial and plant uptake respectively contributed 54%-94%, 1%-46% and 7.5%-14.3% to the N removal in CWs.
- MeSH
- biodegradace MeSH
- biomasa MeSH
- chemické látky znečišťující vodu metabolismus MeSH
- denitrifikace * MeSH
- dusičnany metabolismus MeSH
- izotopy dusíku metabolismus MeSH
- mokřady * MeSH
- odpad tekutý - odstraňování * MeSH
- orobincovité metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Nitrogen discharges from decentralized wastewater treatment (DWT) systems contribute to surface and groundwater contamination. However, the high variability in loading rates, long idle periods and lack of regular maintenance presents a challenge for biological nitrogen removal in DWT. A Tire-Sulfur Hybrid Adsorption Denitrification (T-SHAD) process was developed that combines nitrate (NO3(-)) adsorption to scrap tire chips with sulfur-oxidizing denitrification. This allows the tire chips to adsorb NO3(-) when the influent loading exceeds the denitrification capacity of the biofilm and release it when NO3(-) loading rates are low (e.g. at night). Three waste products, scrap tire chips, elemental sulfur pellets and crushed oyster shells, were used as a medium in adsorption, leaching, microcosm and up-flow packed bed bioreactor studies of NO3(-) removal from synthetic nitrified DWT wastewater. Adsorption isotherms showed that scrap tire chips have an adsorption capacity of 0.66 g NO3(-)-N kg(-1) of scrap tires. Leaching and microcosm studies showed that scrap tires leach bioavailable organic carbon that can support mixotrophic metabolism, resulting in lower effluent SO4(2-) concentrations than sulfur oxidizing denitrification alone. In column studies, the T-SHAD process achieved high NO3(-)-N removal efficiencies under steady state (90%), variable flow (89%) and variable concentration (94%) conditions.
- MeSH
- adsorpce MeSH
- bioreaktory MeSH
- chemické látky znečišťující vodu chemie MeSH
- denitrifikace * MeSH
- dusičnany chemie MeSH
- dusík chemie MeSH
- odpad tekutý - odstraňování ekonomika metody MeSH
- odpadní voda chemie MeSH
- síra chemie MeSH
- tuhý odpad MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
