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Liu G, Yang Z, Du J, He A, Yang H, Xue G, Yu C, Zhang Y. Adding NBPT to urea increases N use efficiency of maize and decreases the abundance of N-cycling soil microbes under reduced fertilizer-N rate on the North China Plain. PLoS One 2020; 15:e0240925. [PMID: 33112905 PMCID: PMC7592763 DOI: 10.1371/journal.pone.0240925] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 10/05/2020] [Indexed: 12/01/2022] Open
Abstract
Urease inhibitor (UI) and nitrification inhibitor (NI) can reduce N losses from agricultural soils but effects of inhibitors on N cycle are unclear. A field experiment was conducted with maize to test effects of UI (N-(n-Butyl) thiophosphoric, NBPT) and NI (3,4-dimethylepyrazolephosphate, DMPP) on N uptake and N-cycling soil microbes. Five treatments were imposed: no N fertilizer input (CK), conventional fertilization (CF) and 80% of urea input with NBPT (80%U+UI), with DMPP (80%U+NI) and with half NBPT and half DMPP (80%U+1/2(UI+NI)). There were no significant differences in biomass between 80%U+UI, 80%U+NI and CF but harvest index was increased under 80%U+UI and 80%U+NI. Compared to CF, N use efficiency of grain under 80%U+UI was increased by 7.1%, whereas grain yield and N uptake under 80%U+1/2(UI+NI) were decreased by 8.2% and 9.4%, respectively. The peak soil NO3‐‐N content was at about 15 days after fertilization (DAF) under CF but 30 DAF under the inhibitor treatments. In soils of 80%U+UI, the activities of urease and nitrate reductase were decreased between 15–45 DAF and between 5–30 DAF. The abundance of N-cycling soil microbes was affected: 80%U+UI and 80%U+NI reduced the copies of the amoA AOA and nir genes at about 15 days and reduced the copies of the amoA AOB gene at about 30 days. Correlation analysis indicated that there were significant positive relationships between amoA AOB gene and NH4+‐N, as well as between nirK gene and NO3‐‐N. Overall, urea applied with NBPT has greater potential for improving maize N use efficiency and inhibiting nitrification under reduced fertilizer-N applications.
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Görres CM, Kammann C. First field estimation of greenhouse gas release from European soil-dwelling Scarabaeidae larvae targeting the genus Melolontha. PLoS One 2020; 15:e0238057. [PMID: 32845917 PMCID: PMC7449402 DOI: 10.1371/journal.pone.0238057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 08/08/2020] [Indexed: 11/24/2022] Open
Abstract
Arthropods are a major soil fauna group, and have the potential to substantially influence the spatial and temporal variability of soil greenhouse gas (GHG) sinks and sources. The overall effect of soil-inhabiting arthropods on soil GHG fluxes still remains poorly quantified since the majority of the available data comes from laboratory experiments, is often controversial, and has been limited to a few species. The main objective of this study was to provide first insights into field-level carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) release of soil-inhabiting larvae of the Scarabaeidae family. Larvae of the genus Melolontha were excavated at various sites in west-central and southern Germany, covering a wide range of different larval developmental stages, larval activity levels, and vegetation types. Excavated larvae were immediately incubated in the field to measure their GHG production. Gaseous carbon release of individual larvae showed a large inter- and intra-site variability which was strongly correlated to larval biomass. This correlation persisted when upscaling individual CO2 and CH4 production to the plot scale. Field release estimates for Melolontha spp. were subsequently upscaled to the European level to derive the first regional GHG release estimates for members of the Scarabaeidae family. Estimates ranged between 10.42 and 409.53 kt CO2 yr-1, and 0.01 and 1.36 kt CH4 yr-1. Larval N2O release was only sporadically observed and not upscaled. For one site, a comparison of field- and laboratory-based GHG production measurements was conducted to assess potential biases introduced by transferring Scarabaeidae larvae to artificial environments. Release strength and variability of captive larvae decreased significantly within two weeks and the correlation between larval biomass and gaseous carbon production disappeared, highlighting the importance of field measurements. Overall, our data show that Scarabaeidae larvae can be significant soil GHG sources and should not be neglected in soil GHG flux research.
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Gillespie LM, Fromin N, Milcu A, Buatois B, Pontoizeau C, Hättenschwiler S. Higher tree diversity increases soil microbial resistance to drought. Commun Biol 2020; 3:377. [PMID: 32665673 PMCID: PMC7360603 DOI: 10.1038/s42003-020-1112-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 06/23/2020] [Indexed: 11/10/2022] Open
Abstract
Predicted increases in drought frequency and severity may change soil microbial functioning. Microbial resistance and recovery to drought depend on plant community characteristics, among other factors, yet how changes in plant diversity modify microbial drought responses is uncertain. Here, we assessed how repeated drying-rewetting cycles affect soil microbial functioning and whether tree species diversity modifies these effects with a microcosm experiment using soils from different European forests. Our results show that microbial aerobic respiration and denitrification decline under drought but are similar in single and mixed tree species forests. However, microbial communities from mixed forests resist drought better than those from mono-specific forests. This positive tree species mixture effect is robust across forests differing in environmental conditions and species composition. Our data show that mixed forests mitigate drought effects on soil microbial processes, suggesting greater stability of biogeochemical cycling in mixed forests should drought frequency increase in the future.
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79
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Ferousi C, Majer SH, DiMucci IM, Lancaster KM. Biological and Bioinspired Inorganic N-N Bond-Forming Reactions. Chem Rev 2020; 120:5252-5307. [PMID: 32108471 PMCID: PMC7339862 DOI: 10.1021/acs.chemrev.9b00629] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The metallobiochemistry underlying the formation of the inorganic N-N-bond-containing molecules nitrous oxide (N2O), dinitrogen (N2), and hydrazine (N2H4) is essential to the lifestyles of diverse organisms. Similar reactions hold promise as means to use N-based fuels as alternative carbon-free energy sources. This review discusses research efforts to understand the mechanisms underlying biological N-N bond formation in primary metabolism and how the associated reactions are tied to energy transduction and organismal survival. These efforts comprise studies of both natural and engineered metalloenzymes as well as synthetic model complexes.
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Monteiro DA, Fonseca EDS, Rodrigues RDAR, da Silva JJN, da Silva EP, Balieiro FDC, Alves BJR, Rachid CTCDC. Structural and functional shifts of soil prokaryotic community due to Eucalyptus plantation and rotation phase. Sci Rep 2020; 10:9075. [PMID: 32493970 PMCID: PMC7270125 DOI: 10.1038/s41598-020-66004-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 04/27/2020] [Indexed: 11/09/2022] Open
Abstract
Agriculture, forestry and other land uses are currently the second highest source of anthropogenic greenhouse gases (GHGs) emissions. In soil, these gases derive from microbial activity, during carbon (C) and nitrogen (N) cycling. To investigate how Eucalyptus land use and growth period impact the microbial community, GHG fluxes and inorganic N levels, and if there is a link among these variables, we monitored three adjacent areas for 9 months: a recently planted Eucalyptus area, fully developed Eucalyptus forest (final of rotation) and native forest. We assessed the microbial community using 16S rRNA gene sequencing and qPCR of key genes involved in C and N cycles. No considerable differences in GHG flux were evident among the areas, but logging considerably increased inorganic N levels. Eucalyptus areas displayed richer and more diverse communities, with selection for specific groups. Land use influenced communities more extensively than the time of sampling or growth phase, although all were significant modulators. Several microbial groups and genes shifted temporally, and inorganic N levels shaped several of these changes. No correlations among microbial groups or genes and GHG were found, suggesting no link among these variables in this short-rotation Eucalyptus study.
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Guo H, Gu J, Wang X, Yu J, Nasir M, Zhang K, Sun W. Microbial driven reduction of N 2O and NH 3 emissions during composting: Effects of bamboo charcoal and bamboo vinegar. JOURNAL OF HAZARDOUS MATERIALS 2020; 390:121292. [PMID: 31810805 DOI: 10.1016/j.jhazmat.2019.121292] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 07/31/2019] [Accepted: 09/22/2019] [Indexed: 06/10/2023]
Abstract
In this study, we systematically analyzed the microbial-driven effects of bamboo charcoal (BC) and bamboo vinegar (BV) on reducing NH3 and N2O emissions during aerobic composting. The results showed that BC and BV improved the nitrogen conversion and compost quality, but the combined BC + BV treatment obtained the best improvements. The BC, BV, and BC + BV treatments reduced the NH3 emissions by 14.35%, 17.90%, and 29.83%, respectively, and the N2O emissions by 44.83%, 55.96%, and 74.53%. BC and BV reduced the NH3 and N2O emissions during composting by controlling ammonia oxidation, where napA, nirK, and nosZ served as useful indicators of the N2O emissions from compost, especially the nirK gene. The dominant nitrifying and denitrifying bacteria belonged to Proteobacteria, and the changes in environmental factors during composting significantly affected the succession of the nitrifying and denitrifying bacterial communities. Nitrosomonas was a key nitrifying bacterial genus in the mesophilic composting period, and BC and BV may have reduced the NH3 emissions by enhancing its conversion to NH4+-N by Nitrosomonas. In addition, norank_p__environmental_samples, unclassified_k__norank_d__Bacteria, and unclassified_p__Proteobacteria were jointly responsible for driving the production of N2O during the compost maturity stage.
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Brambilla S, Soto G, Odorizzi A, Arolfo V, McCormick W, Primo E, Giordano W, Jozefkowicz C, Ayub N. Spontaneous Mutations in the Nitrate Reductase Gene napC Drive the Emergence of Eco-friendly Low-N 2O-Emitting Alfalfa Rhizobia in Regions with Different Climates. MICROBIAL ECOLOGY 2020; 79:1044-1053. [PMID: 31828388 DOI: 10.1007/s00248-019-01473-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 12/03/2019] [Indexed: 06/10/2023]
Abstract
We have recently shown that commercial alfalfa inoculants (e.g., Sinorhizobium meliloti B399), which are closely related to the denitrifier model strain Sinorhizobium meliloti 1021, have conserved nitrate, nitrite, and nitric oxide reductases associated with the production of the greenhouse gas nitrous oxide (N2O) from nitrate but lost the N2O reductase related to the degradation of N2O to gas nitrogen. Here, we screened a library of nitrogen-fixing alfalfa symbionts originating from different ecoregions and containing N2O reductase genes and identified novel rhizobia (Sinorhizobium meliloti INTA1-6) exhibiting exceptionally low N2O emissions. To understand the genetic basis of this novel eco-friendly phenotype, we sequenced and analyzed the genomes of these strains, focusing on their denitrification genes, and found mutations only in the nitrate reductase structural gene napC. The evolutionary analysis supported that, in these natural strains, the denitrification genes were inherited by vertical transfer and that their defective nitrate reductase napC alleles emerged by independent spontaneous mutations. In silico analyses showed that mutations in this gene occurred in ssDNA loop structures with high negative free energy (-ΔG) and that the resulting mutated stem-loop structures exhibited increased stability, suggesting the occurrence of transcription-associated mutation events. In vivo assays supported that at least one of these ssDNA sites is a mutational hot spot under denitrification conditions. Similar benefits from nitrogen fixation were observed when plants were inoculated with the commercial inoculant B399 and strains INTA4-6, suggesting that the low-N2O-emitting rhizobia can be an ecological alternative to the current inoculants without resigning economic profitability.
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83
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He T, Xie D, Ni J, Li Z, Li Z. Nitrous oxide produced directly from ammonium, nitrate and nitrite during nitrification and denitrification. JOURNAL OF HAZARDOUS MATERIALS 2020; 388:122114. [PMID: 31962213 DOI: 10.1016/j.jhazmat.2020.122114] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 12/16/2019] [Accepted: 01/14/2020] [Indexed: 06/10/2023]
Abstract
A hypothermia aerobic denitrifying bacterium, Pseudomonas taiwanensis strain J488, can effectively remove multiple nitrogen sources from wastewater at 15 °C. The ammonium, nitrate and nitrite removal efficiencies were 100 %, 92.61 % and 92.49 %, respectively. Strain J488 could survive with hydroxylamine as sole nitrogen source and its removal efficiency was 97.71 %. The removal efficiency of ammonium was 100 % even in the presence of the classical inhibitors of nitrification allylthiourea and diethyldithiocarbamate. These findings fundamentally changed the picture that the ammonia monooxygenase could be inhibited by the copper chelators of allylthiourea or diethyldithiocarbamate. Similarly, the nitrite removal capacity of strain J488 was not sensitive to inhibition by Pb2+, and its removal efficiency was also 100 %. Additionally, by identifying the intermediates accumulation of nitrification and denitrification, using nitrification and denitrification inhibitors, measuring enzyme activities and determining N2O concentrations, it was demonstrated that N2O could be produced directly from ammonium, nitrate and nitrite.
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84
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de Oliveira TB, de Lucas RC, Scarcella ASDA, Pasin TM, Martínez CA, Polizeli MDLTDM. Perspectives on Exploring Denitrifying Fungi as a Model To Evaluate Nitrous Oxide Production and Reduce Emissions from Agricultural Soils. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:12153-12154. [PMID: 31652054 DOI: 10.1021/acs.jafc.9b06249] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
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85
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Yan X, Zheng S, Qiu D, Yang J, Han Y, Huo Z, Su X, Sun J. Characteristics of N 2O generation within the internal micro-environment of activated sludge flocs under different dissolved oxygen concentrations. BIORESOURCE TECHNOLOGY 2019; 291:121867. [PMID: 31376671 DOI: 10.1016/j.biortech.2019.121867] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 07/18/2019] [Accepted: 07/20/2019] [Indexed: 06/10/2023]
Abstract
Nitrous oxide (N2O) is a strong greenhouse gas that is produced in significant quantities through biological nitrogen removal processes in wastewater treatment plants; however, N2O generation within the internal micro-environment of activated sludge flocs (ASFs) is poorly understood. In this study, microelectrodes and molecular techniques were employed to investigate the concentrations of N2O and other chemicals and the composition and distribution of microbes within ASFs, respectively. The results showed that N2O generation was correlated with the ASF micro-environment, and was significantly influenced by the dissolved oxygen (DO) concentration of the bulk wastewater. Equal N2O, DO, NH4+-N, and NO3--N concentrations were found in small flocs (<100 μm). By contrast, higher N2O generation rates and lower DO, NH4+-N, and NO3--N concentrations were detected in the center of large flocs (>200 μm) compared with those at their surfaces. Microbial structures of varying particle sizes were distinct and depended on the micro-environmental characteristics.
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86
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Gárate M, Moseman-Valtierra S, Moen A. Potential nitrous oxide production by marine shellfish in response to warming and nutrient enrichment. MARINE POLLUTION BULLETIN 2019; 146:236-246. [PMID: 31426152 DOI: 10.1016/j.marpolbul.2019.06.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 06/10/2019] [Accepted: 06/11/2019] [Indexed: 06/10/2023]
Abstract
Bivalves facilitate microbial nitrogen cycling, which can produce nitrous oxide (N2O), a potent greenhouse gas. Potential N2O production by three marine bivalves (Mytilus edulis, Mercenaria mercenaria and Crassostrea virginica) was measured in the laboratory including responses to nitrogen (N) loading and/or warming over short-terms (up to 14 or 28 days). N additions (targeting 100 μM-N ammonium nitrate) or warming (22 °C) individually and in combination were applied with experimental controls (20 μM-N, 19 °C). N2O production rates were higher with N additions for all species, but warming lacked significant direct effects. Ammonium and nitrate concentrations varied but were consistent with nitrification as a potential N2O source for all bivalves. Highest N2O emissions (7.5 nmol N2O g-1 h-1) were from M. edulis under hypoxic conditions coincident with a drop in pH. Macro-epifauna on M. edulis did not significantly alter N2O production. Thus, under short-term hypoxic conditions, micro-organisms in M. edulis guts may be a particularly significant source of N2O.
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Obando M, Correa-Galeote D, Castellano-Hinojosa A, Gualpa J, Hidalgo A, Alché JD, Bedmar E, Cassán F. Analysis of the denitrification pathway and greenhouse gases emissions in Bradyrhizobium sp. strains used as biofertilizers in South America. J Appl Microbiol 2019; 127:739-749. [PMID: 30803109 DOI: 10.1111/jam.14233] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 02/11/2019] [Accepted: 02/19/2019] [Indexed: 02/02/2023]
Abstract
AIMS Greenhouse gases are considered as potential atmospheric pollutants, with agriculture being one of the main emission sources. The practice of inoculating soybean seeds with Bradyrhizobium sp. might contribute to nitrous oxide (N2 O) emissions. We analysed this capacity in five of the most used strains of Bradyrhizobium sp. in South America. METHODS AND RESULTS We analysed the denitrification pathway and N2 O production by Bradyrhizobium japonicum E109 and CPAC15, Bradyrhizobium diazoefficiens CPAC7 and B. elkanii SEMIA 587 and SEMIA 5019, both in free-living conditions and in symbiosis with soybean. The in silico analysis indicated the absence of nosZ genes in B. japonicum and the presence of all denitrification genes in B. diazoefficiens strains, as well as the absence of nirK, norC and nosZ genes in B. elkanii. The in planta analysis confirmed N2 O production under saprophytic conditions or symbiosis with soybean root nodules. In the case of symbiosis, up to 26.1 and 18.4 times higher in plants inoculated with SEMIA5019 and E109, respectively, than in those inoculated with USDA110. CONCLUSIONS The strains E109, SEMIA 5019, CPAC15 and SEMIA 587 showed the highest N2 O production both as free-living cells and in symbiotic conditions in comparison with USDA110 and CPAC7, which do have the nosZ gene. Although norC and nosZ could not be identified in silico or in vitro in SEMIA 587 and SEMIA 5019, these strains showed the capacity to produce N2 O in our experimental conditions. SIGNIFICANCE AND IMPACT OF THE STUDY This is the first report to analyse and confirm the incomplete denitrification capacity and N2 O production in four of the five most used strains of Bradyrhizobium sp. for soybean inoculation in South America.
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Zhang S, Liu F, Luo P, Xiao R, Chen J, Chen L, Wu J. Does rice straw application reduce N 2O emissions from surface flow constructed wetlands for swine wastewater treatment? CHEMOSPHERE 2019; 226:273-281. [PMID: 30933736 DOI: 10.1016/j.chemosphere.2019.03.084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 03/09/2019] [Accepted: 03/13/2019] [Indexed: 06/09/2023]
Abstract
Rice straw was applied often as a carbon source to improve nitrogen removal; however, few studies have considered the effect of rice straw on nitrous oxide (N2O) emission during nitrogen removal in constructed wetlands (CWs). We constructed eighteen combined systems, consisting of rice straw ponds and surface flow CWs to investigate the effect of rice straw application on N2O emission in three strengths of swine wastewater treatments. The results showed rice straw (RS) treatment increased 131.5% of N2O emission factor from low strength CWs, but decreased 37.2-43.7% of N2O emission factors for medium and high strengths compared with no rice straw (NRS) treatment. The RS application led to an average 10.7% increase in the potential denitrification rate, and simultaneously enhanced gene abundances of the total bacteria (16S rRNA), ammonia-oxidising archaea, ammonia-oxidising bacteria, nitrate reductase, and N2O reductase (nosZ) for all strengths CWs. The multiple regression model revealed N2O emissions were strongly related to water temperature, nitrate, chemical oxygen demand, and denitrification genes. The proportion of nosZ gene abundance in 16S rRNA was higher in RS (0.7-1.3%) than NRS (0.4-0.9%) for medium and high strengths, while an opposite trend was observed for low strength. The discrepancy was responsible for increasing or decreasing N2O emission by RS application among different strengths. These findings indicated the effectiveness of RS application to control N2O emissions from the surface flow CWs was related to the pollution level of wastewater.
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Zhang J, Zhuang M, Shan N, Zhao Q, Li H, Wang L. Substituting organic manure for compound fertilizer increases yield and decreases NH 3 and N 2O emissions in an intensive vegetable production systems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 670:1184-1189. [PMID: 31018434 DOI: 10.1016/j.scitotenv.2019.03.191] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 03/13/2019] [Accepted: 03/13/2019] [Indexed: 06/09/2023]
Abstract
Substituting organic manure for compound fertilizer may play an important role in regulating the nitrogen (N) cycle and consequently affecting crop yield in agroecosystems. However, how substituting different organic manures for compound fertilizer affects crop yield and ammonia (NH3) and nitrous oxide (N2O) emissions in the vegetable system during the life-cycle production (including storage and field application) remains poorly elucidated. Thus, we conducted a greenhouse experiment to investigate the effects of substituting organic manure species, i.e., stored swine manure fertilizer (SS), swine manure covered by straw (CS), stored swine fertilizer mixed with biochar (BS), and stored swine manure fertilizer with void expansion (OS) for compound fertilizer (FC) on rapeseed yield and NH3 and N2O emissions in a rapeseed-cropping system in China. The results showed that the total gaseous N losses (NH3 and N2O) were 1.6, 1.4 and 1.1 times higher in SS, CS and OS than FC, respectively. However, total gaseous N losses in BS was 0.9 times less than FC. Compared with FC, rapeseed yield and N uptake in SS and CS were decreased by 17.2-20.2% and 16.0%-28.1%, respectively, but which were increased by 7.3% and 54.1% in BS, respectively. In addition, OS decreased rapeseed yield by 17.2%, but increased N uptake by 8.5%. Therefore, the effects of substituting organic manure for compound fertilizer on rapeseed yield, N uptake, NH3 and N2O varied regarding different organic manure species. Adopting stored swine fertilizer mixed with biochar might be a sound management practice to reduce gaseous N losses and enhance N uptake and yield in intensive vegetable production systems.
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Zhang M, Gu J, Liu Y. Engineering feasibility, economic viability and environmental sustainability of energy recovery from nitrous oxide in biological wastewater treatment plant. BIORESOURCE TECHNOLOGY 2019; 282:514-519. [PMID: 30878291 DOI: 10.1016/j.biortech.2019.03.040] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 03/06/2019] [Accepted: 03/07/2019] [Indexed: 06/09/2023]
Abstract
Currently, the biological wastewater treatment has been challenged by their high energy consumption. An increasing effort has been devoted to exploring energy recovery from nitrous oxide (N2O) as a powerful fuel additive rather than as an unwanted byproduct during biological nitrogen removal. This review aims to offer a holistic and critical analysis of the ideas for N2O production and energy recovery in terms of engineering feasibility, economic viability and environmental sustainability. It turns out that the recoverable energy from N2O produced in municipal wastewater is below 0.03 kWh/m3, which is insignificant compared with the in-plant energy consumption, while complicated process configuration and high cost associated with harvesting and post-purification of N2O will be incurred. An environmental risk related to global climate change due to the emission of residual dissolved N2O is also concerned. Further effort on N2O production and recovery technologies is indeed required to improve the overall energy balance.
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Chen M, Zhou XF, Yu YQ, Liu X, Zeng RJX, Zhou SG, He Z. Light-driven nitrous oxide production via autotrophic denitrification by self-photosensitized Thiobacillus denitrificans. ENVIRONMENT INTERNATIONAL 2019; 127:353-360. [PMID: 30954721 DOI: 10.1016/j.envint.2019.03.045] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 02/27/2019] [Accepted: 03/19/2019] [Indexed: 06/09/2023]
Abstract
N2O (Nitrous oxide, a booster oxidant in rockets) has attracted increasing interest as a means of enhancing energy production, and it can be produced by nitrate (NO3-) reduction in NO3--loading wastewater. However, conventional denitrification processes are often limited by the lack of bioavailable electron donors. In this study, we innovatively propose a self-photosensitized nonphototrophic Thiobacillus denitrificans (T. denitrificans-CdS) that is capable of NO3- reduction and N2O production driven by light. The system converted >72.1 ± 1.1% of the NO3--N input to N2ON, and the ratio of N2O-N in gaseous products was >96.4 ± 0.4%. The relative transcript abundance of the genes encoding the denitrifying proteins in T. denitrificans-CdS after irradiation was significantly upregulated. The photoexcited electrons acted as the dominant electron sources for NO3- reduction by T. denitrificans-CdS. This study provides the first proof of concept for sustainable and low-cost autotrophic denitrification to generate N2O driven by light. The findings also have strong implications for sustainable environmental management because the sunlight-triggered denitrification reaction driven by nonphototrophic microorganisms may widely occur in nature, particularly in a semiconductive mineral-enriched aqueous environment.
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Hu B, Wang T, Ye J, Zhao J, Yang L, Wu P, Duan J, Ye G. Effects of carbon sources and operation modes on the performances of aerobic denitrification process and its microbial community shifts. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2019; 239:299-305. [PMID: 30913480 DOI: 10.1016/j.jenvman.2019.03.063] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 03/10/2019] [Accepted: 03/13/2019] [Indexed: 05/14/2023]
Abstract
Carbon source, operation mode and microbial species have great effects on the synthesis of poly-β-hydroxybutyrate (PHB) which has been identified as the key issue for aerobic denitrification process. In this study, an aerobic denitrification SBR was operated under anoxic/oxic mode and completely oxic mode with the carbon source of CH3COONa and CH3CH2CH2COONa, respectively. Total nitrogen (TN) removal efficiencies, PHB content in activated sludge, production of nitric oxide (NO) and nitrous oxide (N2O) of the process were investigated in great detail. The main results obtained from the trial were: (1) the average TN removal was in the range of 86.11%-90.05%; (2) the maximum TN removal efficiency and the maximum PHB content of the process being achieved when the carbon source of CH3CH2CH2COONa was applied under anoxic/oxic mode; (3) in case of CH3COONa as the carbon source, the concentrations of NO and N2O in the bulk liquid were ∼0.4 mg/L and ∼0.02 mg/L, respectively, while in case of CH3CH2CH2COONa, N2O of ∼0.2 mg/L and NO of ∼2.5 mg/L were recorded and the latter was decreased to ∼1.0 mg/L at the end of the cycle; (4) no obvious dominant genus in case of using CH3COONa, while Plasticicumulans sp. being the major microbial community when using CH3CH2CH2COONa. Overall, the effect of carbon source on microbial community is obvious. Nevertheless, operation mode affects the PHB synthesis, while PHB plays an important role in aerobic denitrification process for achieving a relatively high TN nitrogen removal efficiency. CH3COONa is a better carbon source for aerobic denitrification compared with CH3CH2CH2COONa.
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93
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Thakur IS, Medhi K. Nitrification and denitrification processes for mitigation of nitrous oxide from waste water treatment plants for biovalorization: Challenges and opportunities. BIORESOURCE TECHNOLOGY 2019; 282:502-513. [PMID: 30898409 DOI: 10.1016/j.biortech.2019.03.069] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/12/2019] [Accepted: 03/13/2019] [Indexed: 06/09/2023]
Abstract
Nitrous oxide (N2O) is a potent greenhouse gas. Even though its emissions is much lesser than CO2 but its global warming potential (GWP) is 298 times more than CO2. N2O emissions from wastewater treatment plants was caused due to incomplete nitrification or incomplete denitrification catalyzed by ammonia-oxidizing bacteria and heterotrophic denitrifiers. Low dissolved oxygen, high nitrite accumulation, change in optimal pH or temperature, fluctuation in C/N ratio, short solid retention time and non-availability of Cu ions were responsible for higher N2O leakage. Regulation of enzyme metabolic pathways involved in N2O production and reduction has also been reviewed. Sequential bioreactors, bioscrubbers, membrane biofilters usage have helped microbial nitrification-denitrification processes in succumbing N2O production in wastewater treatment plants. Reduction of N2O negativity has been studied through its valorization for the formation of value added products such as biopolymers has led to biorefinery approaches as an upcoming mitigation strategy.
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94
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Ganesan S, Vadivelu VM. Effect of external hydrazine addition on anammox reactor start-up time. CHEMOSPHERE 2019; 223:668-674. [PMID: 30802832 DOI: 10.1016/j.chemosphere.2019.02.104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 02/13/2019] [Accepted: 02/16/2019] [Indexed: 06/09/2023]
Abstract
Hydrazine is an intermediate product of the anaerobic ammonium oxidation (Anammox) process where both ammonium and nitrite in wastewater are converted to nitrogen gas by bacteria. In this study the effect of external hydrazine addition (5, 10, 15, and 20 mg/L) on the start-up period of the Anammox process was studied using sequencing batch reactors (SBRs). The SBR with an addition of 10 mg/L hydrazine took only 7 weeks to stabilize and achieve the maximum removal of ammonium and nitrite, whereas the SBR without the addition of hydrazine took 12 weeks. The amount of Heme C extracted from the biomass indicated that externally added hydrazine accelerated the growth of Anammox bacteria and reduced the release of nitrous oxide gas from the reactors.
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95
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Kits KD, Jung MY, Vierheilig J, Pjevac P, Sedlacek CJ, Liu S, Herbold C, Stein LY, Richter A, Wissel H, Brüggemann N, Wagner M, Daims H. Low yield and abiotic origin of N 2O formed by the complete nitrifier Nitrospira inopinata. Nat Commun 2019; 10:1836. [PMID: 31015413 PMCID: PMC6478695 DOI: 10.1038/s41467-019-09790-x] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Accepted: 03/27/2019] [Indexed: 12/11/2022] Open
Abstract
Nitrous oxide (N2O) and nitric oxide (NO) are atmospheric trace gases that contribute to climate change and affect stratospheric and ground-level ozone concentrations. Ammonia oxidizing bacteria (AOB) and archaea (AOA) are key players in the nitrogen cycle and major producers of N2O and NO globally. However, nothing is known about N2O and NO production by the recently discovered and widely distributed complete ammonia oxidizers (comammox). Here, we show that the comammox bacterium Nitrospira inopinata is sensitive to inhibition by an NO scavenger, cannot denitrify to N2O, and emits N2O at levels that are comparable to AOA but much lower than AOB. Furthermore, we demonstrate that N2O formed by N. inopinata formed under varying oxygen regimes originates from abiotic conversion of hydroxylamine. Our findings indicate that comammox microbes may produce less N2O during nitrification than AOB.
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96
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Jiang Y, Poh LS, Lim CP, Ng WJ. Impact of free nitrous acid shock and dissolved oxygen limitation on nitritation maintenance and nitrous oxide emission in a membrane bioreactor. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 660:11-17. [PMID: 30639708 DOI: 10.1016/j.scitotenv.2019.01.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 01/03/2019] [Accepted: 01/03/2019] [Indexed: 06/09/2023]
Abstract
This study investigated the initiation and maintenance of nitritation in a membrane bioreactor (MBR) with long solids retention time (SRT) of 43.8 days. Nitritation was initiated within 65 days in the MBR via dissolved oxygen (DO) limitation (<0.5 mg/L). However, nitrite oxidizing bacteria (NOB) (Nitrospira and Nitrobacter) acclimated to the low DO environment and proliferated from day 81, leading to nitrate accumulation. Thereafter, the combined strategy of DO limitation and in-situ generated free nitrous acid (FNA) shock successfully restored and maintained stable nitritation for >70 days. Quantitative polymerase chain reaction (qPCR) results showed that cell abundances of Nitrospira and Nitrobacter decreased by between 50.0 to 68.9% and 60.6 to 96.4%, respectively following the FNA shocks. The maximum ammonium loading rate achieved was 1.81 kg N/(m3 day) with ammonium removal ratio and nitrite accumulation ratio of over 0.97 and 0.96, respectively. Average emission rate of N2O from the MBR was 2.1 ± 0.72% of ammonium removed. FNA shock on day 195 reduced the N2O emission by 13.6%. The strategy developed in this study verified that spiked FNA shock together with DO limitation can be used for maintaining nitritation in MBRs with long SRTs. This method can potentially allow for maintaining nitritation at relatively low capital and operating expenditure when treating high concentration ammonium wastewater.
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97
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Cassman NA, Soares JR, Pijl A, Lourenço KS, van Veen JA, Cantarella H, Kuramae EE. Nitrification inhibitors effectively target N 2 O-producing Nitrosospira spp. in tropical soil. Environ Microbiol 2019; 21:1241-1254. [PMID: 30735001 PMCID: PMC6850170 DOI: 10.1111/1462-2920.14557] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 01/09/2019] [Accepted: 02/04/2019] [Indexed: 01/01/2023]
Abstract
The nitrification inhibitors (NIs) 3,4-dimethylpyrazole (DMPP) and dicyandiamide (DCD) can effectively reduce N2 O emissions; however, which species are targeted and the effect of these NIs on the microbial nitrifier community is still unclear. Here, we identified the ammonia oxidizing bacteria (AOB) species linked to N2 O emissions and evaluated the effects of urea and urea with DCD and DMPP on the nitrifying community in a 258 day field experiment under sugarcane. Using an amoA AOB amplicon sequencing approach and mining a previous dataset of 16S rRNA sequences, we characterized the most likely N2 O-producing AOB as a Nitrosospira spp. and identified Nitrosospira (AOB), Nitrososphaera (archaeal ammonia oxidizer) and Nitrospira (nitrite-oxidizer) as the most abundant, present nitrifiers. The fertilizer treatments had no effect on the alpha and beta diversities of the AOB communities. Interestingly, we found three clusters of co-varying variables with nitrifier operational taxonomic units (OTUs): the N2 O-producing AOB Nitrosospira with N2 O, NO3 - , NH4 + , water-filled pore space (WFPS) and pH; AOA Nitrososphaera with NO3 - , NH4 + and pH; and AOA Nitrososphaera and NOB Nitrospira with NH4 + , which suggests different drivers. These results support the co-occurrence of non-N2 O-producing Nitrososphaera and Nitrospira in the unfertilized soils and the promotion of N2 O-producing Nitrosospira under urea fertilization. Further, we suggest that DMPP is a more effective NI than DCD in tropical soil under sugarcane.
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98
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Zhao Y, Zhang Z, Li Z, Wang S, Tan C, Fan L, Pan J. Does intermittent aeration and/or an influent distributary affect nitrogen removal and nitrous oxide emission of an ecological soil wastewater infiltration system? WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2019; 79:1417-1425. [PMID: 31123241 DOI: 10.2166/wst.2019.144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The effect of intermittent aeration and an influent distributary on NH4 +-N removal, total nitrogen (TN) removal, nitrous oxide (N2O) emission and the abundances of nitrogen removal and N2O emission functional genes in four types of ecological soil wastewater infiltration systems (ESWISs) (which were conventional ESWIS 1 (operated without aeration and influent distributary), ESWIS 2 (operated with intermittent aeration), ESWIS 3 (operated with influent distributary) and ESWIS 4 (operated with intermittent aeration and influent distributary)) were studied. Intermittent aeration in ESWIS 2 and 4 created aerobic conditions above 50 cm depth of the matrix and anoxic or anaerobic conditions in the lower matrix (below 80 cm depth). ESWIS 4 improved NH4 +-N (to 90.1%) and TN (to 87.8%) removal efficiencies and increased the abundances of eight nitrogen removal and N2O emission functional genes (amoA, nxrA, narG, napA, nirS, nirK, qnorB and nosZ) in contrast with other ESWISs. The combination of intermittent aeration and influent distributary achieved the lowest N2O emission rate of 34.7 mg/(m2 d) in ESWIS 4. Intermittent aeration combined with influent distributary was recommended for ESWISs to enhance nitrogen removal and reduce N2O emission.
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99
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Huang X, Xu Y, He T, Jia H, Feng M, Xiang S, Wang S, Ni J, Xie D, Li Z. Ammonium transformed into nitrous oxide via nitric oxide by Pseudomonas putida Y-9 under aerobic conditions without hydroxylamine as intermediate. BIORESOURCE TECHNOLOGY 2019; 277:87-93. [PMID: 30660065 DOI: 10.1016/j.biortech.2019.01.040] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 01/07/2019] [Accepted: 01/08/2019] [Indexed: 06/09/2023]
Abstract
Previous studies have reported that hydroxylamine (NH2OH) is an inevitable intermediate of the ammonium (NH4+) oxidation pathway under aerobic conditions. In this study, Pseudomonas putida Y-9 was found to oxidize ammonium into N2O via NO without the accumulation of NH2OH and NO2- under aerobic conditions. NH2OH was nearly completely transformed into NO2- whether NH4+ was present in the medium, and NH4+ could accelerate the transformation of NH2OH to NO2- by promoting Y-9 growth. NH4+ was oxidized rapidly by Y-9 with or without the presence of NH2OH in the medium, and the decrease of total nitrogen reached 30.65 mg/L and 39.38 mg/L, respectively, which indicates that NH2OH inhibits the transformation efficiency of NH4+ to N2O. Gene amplification and enzyme assays demonstrated that ammonia monooxygenase doesn't exist in Y-9. All results show that NH4+ can be transformed into N2O via NO by Y-9 under aerobic conditions without NH2OH as intermediate.
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100
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Han W, Luo G, Luo B, Yu C, Wang H, Chang J, Ge Y. Effects of plant diversity on greenhouse gas emissions in microcosms simulating vertical constructed wetlands with high ammonium loading. J Environ Sci (China) 2019; 77:229-237. [PMID: 30573087 DOI: 10.1016/j.jes.2018.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 08/02/2018] [Accepted: 08/03/2018] [Indexed: 06/09/2023]
Abstract
Wastewater with relatively high nitrogen concentrations is a major source of nitrous oxide (N2O) and methane (CH4) emissions and exerts multiple stresses on the environment. Studies have shown that plant diversity plays an important role in ecosystem functioning. However, the effects of plant species diversity on CH4 and N2O emissions under high ammonium (NH4+-N) loading rates remain unclear. In this study, a microcosm experiment simulating vertical constructed wetlands supplied with high NH4+-N water levels was established. The treatments included four species richness levels (1, 2, 3, 4) and 15 species compositions. There was no significant relationship between species richness and N2O emissions. However, N2O emissions were significantly reduced by specific plant species composition. Notably, the communities with the presence of Rumex japonicus L. reduced N2O emissions by 62% compared to communities without this species. This reduction in N2O emissions may have been a result of decreased N concentrations and increased plant biomass. CH4 emissions did not respond to plant species richness or species identity. Overall, plant species identity surpassed species richness in lowering N2O emissions from constructed wetlands with high NH4+-N water. The results also suggest that communities with R. japonicus could achieve higher N removal and lower greenhouse gas emissions than other wetland species.
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