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Li J, Wan X, Wang H, Zhang Y, Ma Z, Yang W, Hu Y. Electrospun nanofibers electrostatically adsorb heterotrophic nitrifying and aerobic denitrifying bacteria to degrade nitrogen in wastewater. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 353:120199. [PMID: 38316072 DOI: 10.1016/j.jenvman.2024.120199] [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: 08/27/2023] [Revised: 12/13/2023] [Accepted: 01/20/2024] [Indexed: 02/07/2024]
Abstract
Nanofibers were prepared by electrospinning a mixture of polycaprolactone and silica, and modified to improve the hydrophilicity and stability of the material and to degrade nitrogenous wastewater by adsorbing heterotrophic nitrifying aerobic denitrifying (Ochrobactrum anthropic). The immobilized bacteria showed highly efficient simultaneous nitrification-denitrification ability, which could convert nearly 90 % of the initial nitrogen into gaseous nitrogen under aerobic conditions, and the average TN removal rate reached 5.59 mg/L/h. The average ammonia oxidation rate of bacteria immobilized by modified nanofibers was 7.36 mg/L/h, compared with 6.3 mg/L/h for free bacteria and only 4.23 mg/L/h for unmodified nanofiber-immobilized bacteria. Kinetic studies showed that modified nanofiber-immobilized bacteria complied with first-order degradation kinetics, and the effects of extreme pH, temperature, and salinity on immobilized bacteria were significantly reduced, while the degradation rate of free bacteria produced larger fluctuations. In addition, the immobilized bacterial nanofibers were reused five times, and the degradation rate remained stable at more than 80 %. At the same time, the degradation rate can still reach 50 % after 6 months of storage at 4 °C. It also demonstrated good nitrogen removal in practical wastewater treatment.
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Affiliation(s)
- Jixiang Li
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30, South Puzhu Road, Nanjing, 211816, PR China; State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, No. 30, South Puzhu Road, Nanjing, 211816, PR China
| | - Xiaoru Wan
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30, South Puzhu Road, Nanjing, 211816, PR China; State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, No. 30, South Puzhu Road, Nanjing, 211816, PR China
| | - HeTianai Wang
- College of Food Science and Light Industry, Nanjing Tech University, No. 30, South Puzhu Road, Nanjing, 211816, PR China
| | - Yanju Zhang
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30, South Puzhu Road, Nanjing, 211816, PR China; State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, No. 30, South Puzhu Road, Nanjing, 211816, PR China
| | - Zilin Ma
- College of 2011, Nanjing Tech University, No. 30, South Puzhu Road, Nanjing, 211816, PR China
| | - Wenge Yang
- School of Pharmaceutical Sciences, Nanjing Tech University, No. 30, South Puzhu Road, Nanjing, 211816, PR China.
| | - Yonghong Hu
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30, South Puzhu Road, Nanjing, 211816, PR China; College of Food Science and Light Industry, Nanjing Tech University, No. 30, South Puzhu Road, Nanjing, 211816, PR China.
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Zhang Z, Zhang H, Al-Gabr HM, Jin H, Zhang K. Performances and enhanced mechanisms of nitrogen removal in a submerged membrane bioreactor coupled sponge iron system. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 318:115505. [PMID: 35753132 DOI: 10.1016/j.jenvman.2022.115505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 05/07/2022] [Accepted: 06/07/2022] [Indexed: 06/15/2023]
Abstract
Sponge iron is a potential material for nitrogen removal, but lack of a study about nitrogen removal in a membrane bioreactor (MBR) coupled with sponge iron. The performances and mechanisms of nitrogen removal of SI-MBR were investigated and compared it with that in GAC-MBR. The results showed that the average rate of organic matter removal in the SI-MBR was 92.74%, which was higher than that in the GAC-MBR (87.48%). And the average effluent NO2--N and NO3--N concentration in the SI-MBR (0.02 mg/L and 3.73 mg/L) was lower than that in the GAC-MBR (0.05 mg/L and 7.51 mg/L). Meanwhile, the highest nitrification rate and denitrification rate was respectively 3.544 ± 0.25 mg/(g VSS·h) and 6.643 ± 0.2 mg/(g VSS·h) in the SI-MBR, which was higher than that (3.094 ± 0.25 mg/(g VSS·h) and (6.376 ± 0.2 mg/(g VSS·h)) in the GAC-MBR. Additionally, the bacterial activities (e.g., DHA activity and respiratory activity) were obviously enhanced through the iron ion from sponge iron. The bacterial community in the SI-MBR system was more richness and diverse than that in the GAC-MBR. Ultimately, the mechanisms of enhanced biological nitrogen removal with sponge iron in MBR were analyzed. On the surface of sponge iron, the DIRB and FOB could use the iron ion from sponge iron as the electron transfer to improve the nitrogen and organic removal. With sponge iron, there is not only the nitrification bacteria and heterotrophic denitrifying microorganism enriched, but also the autotrophic denitrifying bacteria abounded obviously. The autotrophic denitrifying bacteria could use Fe(II) as an electron donor to achieve denitrification and enhance the nitrogen removal.
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Affiliation(s)
- Zhuowei Zhang
- NingboTech University, 315000, China; College of Water Sciences, Beijing Normal University, Beijing, 100875, China
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Salas A, Cabrera JJ, Jiménez-Leiva A, Mesa S, Bedmar EJ, Richardson DJ, Gates AJ, Delgado MJ. Bacterial nitric oxide metabolism: Recent insights in rhizobia. Adv Microb Physiol 2021; 78:259-315. [PMID: 34147187 DOI: 10.1016/bs.ampbs.2021.05.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nitric oxide (NO) is a reactive gaseous molecule that has several functions in biological systems depending on its concentration. At low concentrations, NO acts as a signaling molecule, while at high concentrations, it becomes very toxic due to its ability to react with multiple cellular targets. Soil bacteria, commonly known as rhizobia, have the capacity to establish a N2-fixing symbiosis with legumes inducing the formation of nodules in their roots. Several reports have shown NO production in the nodules where this gas acts either as a signaling molecule which regulates gene expression, or as a potent inhibitor of nitrogenase and other plant and bacteria enzymes. A better understanding of the sinks and sources of NO in rhizobia is essential to protect symbiotic nitrogen fixation from nitrosative stress. In nodules, both the plant and the microsymbiont contribute to the production of NO. From the bacterial perspective, the main source of NO reported in rhizobia is the denitrification pathway that varies significantly depending on the species. In addition to denitrification, nitrate assimilation is emerging as a new source of NO in rhizobia. To control NO accumulation in the nodules, in addition to plant haemoglobins, bacteroids also contribute to NO detoxification through the expression of a NorBC-type nitric oxide reductase as well as rhizobial haemoglobins. In the present review, updated knowledge about the NO metabolism in legume-associated endosymbiotic bacteria is summarized.
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Affiliation(s)
- Ana Salas
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Juan J Cabrera
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain; School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - Andrea Jiménez-Leiva
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Socorro Mesa
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Eulogio J Bedmar
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - David J Richardson
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - Andrew J Gates
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - María J Delgado
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain.
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Torregrosa-Crespo J, Pire C, Martínez-Espinosa RM, Bergaust L. Denitrifying haloarchaea within the genus Haloferax display divergent respiratory phenotypes, with implications for their release of nitrogenous gases. Environ Microbiol 2018; 21:427-436. [PMID: 30421557 DOI: 10.1111/1462-2920.14474] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 11/05/2018] [Indexed: 11/30/2022]
Abstract
Haloarchaea are extremophiles, generally thriving at high temperatures and salt concentrations, thus, with limited access to oxygen. As a strategy to maintain a respiratory metabolism, many halophilic archaea are capable of denitrification. Among them are members of the genus Haloferax, which are abundant in saline/hypersaline environments. Three reported haloarchaeal denitrifiers, Haloferax mediterranei, Haloferax denitrificans and Haloferax volcanii, were characterized with respect to their denitrification phenotype. A semi-automatic incubation system was used to monitor the depletion of electron acceptors and accumulation of gaseous intermediates in batch cultures under a range of conditions. Out of the species tested, only H. mediterranei was able to consistently reduce all available N-oxyanions to N2 , while the other two released significant amounts of NO and N2 O, which affect tropospheric and stratospheric chemistries respectively. The prevalence and magnitude of hypersaline ecosystems are on the rise due to climate change and anthropogenic activity. Thus, the biology of halophilic denitrifiers is inherently interesting, due to their contribution to the global nitrogen cycle, and potential application in bioremediation. This work is the first detailed physiological study of denitrification in haloarchaea, and as such a seed for our understanding of the drivers of nitrogen turnover in hypersaline systems.
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Affiliation(s)
- Javier Torregrosa-Crespo
- Departamento de Agroquímica y Bioquímica, División de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Alicante, Carretera San Vicente del Raspeig s/n - 03690 San Vicente del Raspeig, Alicante, Spain
| | - Carmen Pire
- Departamento de Agroquímica y Bioquímica, División de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Alicante, Carretera San Vicente del Raspeig s/n - 03690 San Vicente del Raspeig, Alicante, Spain
| | - Rosa María Martínez-Espinosa
- Departamento de Agroquímica y Bioquímica, División de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Alicante, Carretera San Vicente del Raspeig s/n - 03690 San Vicente del Raspeig, Alicante, Spain
| | - Linda Bergaust
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences. Chr. M, Falsens vei 1 - 1430, Ås, Norway
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Kahle M, Ter Beek J, Hosler JP, Ädelroth P. The insertion of the non-heme Fe B cofactor into nitric oxide reductase from P. denitrificans depends on NorQ and NorD accessory proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:1051-1058. [PMID: 29874552 DOI: 10.1016/j.bbabio.2018.05.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 05/27/2018] [Accepted: 05/31/2018] [Indexed: 10/14/2022]
Abstract
Bacterial NO reductases (NOR) catalyze the reduction of NO into N2O, either as a step in denitrification or as a detoxification mechanism. cNOR from Paracoccus (P.) denitrificans is expressed from the norCBQDEF operon, but only the NorB and NorC proteins are found in the purified NOR complex. Here, we established a new purification method for the P. denitrificans cNOR via a His-tag using heterologous expression in E. coli. The His-tagged enzyme is both structurally and functionally very similar to non-tagged cNOR. We were also able to express and purify cNOR from the structural genes norCB only, in absence of the accessory genes norQDEF. The produced protein is a stable NorCB complex containing all hemes and it can bind gaseous ligands (CO) to heme b3, but it is catalytically inactive. We show that this deficient cNOR lacks the non-heme iron cofactor FeB. Mutational analysis of the nor gene cluster revealed that it is the norQ and norD genes that are essential to form functional cNOR. NorQ belongs to the family of MoxR P-loop AAA+ ATPases, which are in general considered to facilitate enzyme activation processes often involving metal insertion. Our data indicates that NorQ and NorD work together in order to facilitate non-heme Fe insertion. This is noteworthy since in many cases Fe cofactor binding occurs spontaneously. We further suggest a model for NorQ/D-facilitated metal insertion into cNOR.
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Affiliation(s)
- Maximilian Kahle
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Josy Ter Beek
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Jonathan P Hosler
- Department of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, MS 39216, United States
| | - Pia Ädelroth
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.
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Torregrosa-Crespo J, González-Torres P, Bautista V, Esclapez JM, Pire C, Camacho M, Bonete MJ, Richardson DJ, Watmough NJ, Martínez-Espinosa RM. Analysis of multiple haloarchaeal genomes suggests that the quinone-dependent respiratory nitric oxide reductase is an important source of nitrous oxide in hypersaline environments. ENVIRONMENTAL MICROBIOLOGY REPORTS 2017; 9:788-796. [PMID: 28925557 DOI: 10.1111/1758-2229.12596] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Microorganisms, including Bacteria and Archaea, play a key role in denitrification, which is the major mechanism by which fixed nitrogen returns to the atmosphere from soil and water. While the enzymology of denitrification is well understood in Bacteria, the details of the last two reactions in this pathway, which catalyse the reduction of nitric oxide (NO) via nitrous oxide (N2 O) to nitrogen (N2 ), are little studied in Archaea, and hardly at all in haloarchaea. This work describes an extensive interspecies analysis of both complete and draft haloarchaeal genomes aimed at identifying the genes that encode respiratory nitric oxide reductases (Nors). The study revealed that the only nor gene found in haloarchaea is one that encodes a single subunit quinone dependent Nor homologous to the qNor found in bacteria. This surprising discovery is considered in terms of our emerging understanding of haloarchaeal bioenergetics and NO management.
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Affiliation(s)
- Javier Torregrosa-Crespo
- Department of Agrochemistry and Biochemistry. Faculty of Science, University of Alicante, Ap. 99, E-03080 Alicante, Spain
| | - Pedro González-Torres
- Bioinformatics and Genomics Program, Centre for Genomic Regulation (CRG), Dr. Aiguader, 88. 08003 Barcelona, Spain
| | - Vanesa Bautista
- Department of Agrochemistry and Biochemistry. Faculty of Science, University of Alicante, Ap. 99, E-03080 Alicante, Spain
| | - Julia M Esclapez
- Department of Agrochemistry and Biochemistry. Faculty of Science, University of Alicante, Ap. 99, E-03080 Alicante, Spain
| | - Carmen Pire
- Department of Agrochemistry and Biochemistry. Faculty of Science, University of Alicante, Ap. 99, E-03080 Alicante, Spain
| | - Mónica Camacho
- Department of Agrochemistry and Biochemistry. Faculty of Science, University of Alicante, Ap. 99, E-03080 Alicante, Spain
| | - María José Bonete
- Department of Agrochemistry and Biochemistry. Faculty of Science, University of Alicante, Ap. 99, E-03080 Alicante, Spain
| | - David J Richardson
- Centre for Molecular Structure and Biochemistry, School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Nicholas J Watmough
- Centre for Molecular Structure and Biochemistry, School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Rosa María Martínez-Espinosa
- Department of Agrochemistry and Biochemistry. Faculty of Science, University of Alicante, Ap. 99, E-03080 Alicante, Spain
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Roco CA, Bergaust LL, Bakken LR, Yavitt JB, Shapleigh JP. Modularity of nitrogen-oxide reducing soil bacteria: linking phenotype to genotype. Environ Microbiol 2016; 19:2507-2519. [PMID: 26914200 DOI: 10.1111/1462-2920.13250] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 01/25/2016] [Indexed: 12/26/2022]
Abstract
Model denitrifiers convert NO3- to N2 , but it appears that a significant fraction of natural populations are truncated, conducting only one or two steps of the pathway. To better understand the diversity of partial denitrifiers in soil and whether discrepancies arise between the presence of known N-oxide reductase genes and phenotypic features, bacteria able to reduce NO3- to NO2- were isolated from soil, N-oxide gas products were measured for eight isolates, and six were genome sequenced. Gas phase analyses revealed that two were complete denitrifiers, which genome sequencing corroborated. The remaining six accumulated NO and N2 O to varying degrees and genome sequencing of four indicated that two isolates held genes encoding nitrate reductase as the only dissimilatory N-oxide reductase, one contained genes for both nitrate and nitric oxide reductase, and one had nitrate and nitrite reductase. The results demonstrated that N-oxide production was not always predicted by the genetic potential and suggested that partial denitrifiers could be readily isolated among soil bacteria. This supported the hypothesis that each N-oxide reductase could provide a selectable benefit on its own, and therefore, reduction of nitrate to dinitrogen may not be obligatorily linked to complete denitrifiers but instead a consequence of a functionally diverse community.
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Affiliation(s)
| | - Linda L Bergaust
- Department of Chemistry, Biotechnology and Food Sciences, Norwegian University of Life Sciences, Ǻs, Norway
| | - Lars R Bakken
- Department of Plant and Environmental Sciences, Norwegian University of Life Sciences, Ǻs, Norway
| | - Joseph B Yavitt
- Department of Natural Resources, Cornell University, Ithaca, NY, USA
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Highly diverse nirK genes comprise two major clades that harbour ammonium-producing denitrifiers. BMC Genomics 2016; 17:155. [PMID: 26923558 PMCID: PMC4770552 DOI: 10.1186/s12864-016-2465-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 02/12/2016] [Indexed: 01/09/2023] Open
Abstract
Background Copper dependent nitrite reductase, NirK, catalyses the key step in denitrification, i.e. nitrite reduction to nitric oxide. Distinct structural NirK classes and phylogenetic clades of NirK-type denitrifiers have previously been observed based on a limited set of NirK sequences, however, their environmental distribution or ecological strategies are currently unknown. In addition, environmental nirK-type denitrifiers are currently underestimated in PCR-dependent surveys due to primer coverage limitations that can be attributed to their broad taxonomic diversity and enormous nirK sequence divergence. Therefore, we revisited reported analyses on partial NirK sequences using a taxonomically diverse, full-length NirK sequence dataset. Results Division of NirK sequences into two phylogenetically distinct clades was confirmed, with Clade I mainly comprising Alphaproteobacteria (plus some Gamma- and Betaproteobacteria) and Clade II harbouring more diverse taxonomic groups like Archaea, Bacteroidetes, Chloroflexi, Gemmatimonadetes, Nitrospirae, Firmicutes, Actinobacteria, Planctomycetes and Proteobacteria (mainly Beta and Gamma). Failure of currently available primer sets to target diverse NirK-type denitrifiers in environmental surveys could be attributed to mismatches over the whole length of the primer binding regions including the 3′ site, with Clade II sequences containing higher sequence divergence than Clade I sequences. Simultaneous presence of both the denitrification and DNRA pathway could be observed in 67 % of all NirK-type denitrifiers. Conclusion The previously reported division of NirK into two distinct phylogenetic clades was confirmed using a taxonomically diverse set of full-length NirK sequences. Enormous sequence divergence of nirK gene sequences, probably due to variable nirK evolutionary trajectories, will remain an issue for covering diverse NirK-type denitrifiers in amplicon-based environmental surveys. The potential of a single organism to partition nitrate to either denitrification or dissimilatory nitrate reduction to ammonium appeared to be more widespread than originally anticipated as more than half of all NirK-type denitrifiers were shown to contain both pathways in their genome. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2465-0) contains supplementary material, which is available to authorized users.
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Torres M, Simon J, Rowley G, Bedmar E, Richardson D, Gates A, Delgado M. Nitrous Oxide Metabolism in Nitrate-Reducing Bacteria: Physiology and Regulatory Mechanisms. Adv Microb Physiol 2016; 68:353-432. [PMID: 27134026 DOI: 10.1016/bs.ampbs.2016.02.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Nitrous oxide (N2O) is an important greenhouse gas (GHG) with substantial global warming potential and also contributes to ozone depletion through photochemical nitric oxide (NO) production in the stratosphere. The negative effects of N2O on climate and stratospheric ozone make N2O mitigation an international challenge. More than 60% of global N2O emissions are emitted from agricultural soils mainly due to the application of synthetic nitrogen-containing fertilizers. Thus, mitigation strategies must be developed which increase (or at least do not negatively impact) on agricultural efficiency whilst decrease the levels of N2O released. This aim is particularly important in the context of the ever expanding population and subsequent increased burden on the food chain. More than two-thirds of N2O emissions from soils can be attributed to bacterial and fungal denitrification and nitrification processes. In ammonia-oxidizing bacteria, N2O is formed through the oxidation of hydroxylamine to nitrite. In denitrifiers, nitrate is reduced to N2 via nitrite, NO and N2O production. In addition to denitrification, respiratory nitrate ammonification (also termed dissimilatory nitrate reduction to ammonium) is another important nitrate-reducing mechanism in soil, responsible for the loss of nitrate and production of N2O from reduction of NO that is formed as a by-product of the reduction process. This review will synthesize our current understanding of the environmental, regulatory and biochemical control of N2O emissions by nitrate-reducing bacteria and point to new solutions for agricultural GHG mitigation.
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