Conversion of molecular nitrogen into biologically accessible nitrogen compounds
Nitrogen fixation is a chemical process by which molecular nitrogen (N 2), which has a strong triple covalent bond, is converted into ammonia (NH 3) or related nitrogenous compounds, typically in soil or aquatic systems[1] but also in industry. The nitrogen in air is molecular dinitrogen, a relatively nonreactive molecule that is metabolically useless to all but a few microorganisms. Biological nitrogen fixation or diazotrophy is an important microbe-mediated process that converts dinitrogen (N2) gas to ammonia (NH3) using the nitrogenase protein complex (Nif).[2][3]
Nitrogen fixation is essential to life because fixed inorganic nitrogen compounds are required for the biosynthesis of all nitrogen-containing organic compounds, such as amino acids and proteins, nucleoside triphosphates and nucleic acids. As part of the nitrogen cycle, it is essential for agriculture and the manufacture of fertilizer. It is also, indirectly, relevant to the manufacture of all nitrogen chemical compounds, which include some explosives, pharmaceuticals, and dyes.
Nitrogen fixation is carried out naturally in soil by microorganisms termed diazotrophs that include bacteria, such as Azotobacter and Rhizobia, and archaea. Some nitrogen-fixing bacteria have symbiotic relationships with plant groups, especially legumes.[4] Looser non-symbiotic relationships between diazotrophs and plants are often referred to as associative, as seen in nitrogen fixation on rice roots. Nitrogen fixation occurs between some termites and fungi.[5] It occurs naturally in the air by means of NOx production by lightning.[6][7]
All biological reactions involving the process of nitrogen fixation are catalyzed by enzymes called nitrogenases.[8] These enzymes contain iron, often with a second metal, usually molybdenum but sometimes vanadium.
^Zahran HH (December 1999). "Rhizobium-legume symbiosis and nitrogen fixation under severe conditions and in an arid climate". Microbiology and Molecular Biology Reviews. 63 (4): 968–89, table of contents. doi:10.1128/MMBR.63.4.968-989.1999. PMC 98982. PMID 10585971.
^Sapountzis P, de Verges J, Rousk K, Cilliers M, Vorster BJ, Poulsen M (2016). "Potential for Nitrogen Fixation in the Fungus-Growing Termite Symbiosis". Frontiers in Microbiology. 7: 1993. doi:10.3389/fmicb.2016.01993. PMC 5156715. PMID 28018322.
^Slosson E (1919). Creative Chemistry. New York, NY: The Century Co. pp. 19–37.
^Hill RD, Rinker RG, Wilson HD (1979). "Atmospheric Nitrogen Fixation by Lightning". J. Atmos. Sci. 37 (1): 179–192. Bibcode:1980JAtS...37..179H. doi:10.1175/1520-0469(1980)037<0179:ANFBL>2.0.CO;2.
^Wagner SC (2011). "Biological Nitrogen Fixation". Nature Education Knowledge. 3 (10): 15. Archived from the original on 13 September 2018. Retrieved 29 January 2019.
Nitrogenfixation is a chemical process by which molecular nitrogen (N 2), which has a strong triple covalent bond, is converted into ammonia (NH 3) or...
conversion of nitrogen can be carried out through both biological and physical processes. Important processes in the nitrogen cycle include fixation, ammonification...
product of sucrose is the direct carbon source for the bacteroid. Nitrogenfixation in the nodule is very oxygen sensitive. Legume nodules harbor an iron...
thalassa's hosts and host preferences. Nitrogenfixation, which is the reduction of N2 to biologically available nitrogen, is an important source of N for aquatic...
plants, and releasing it in the form of ammonium ions into the soil (nitrogenfixation). In addition to being a model organism for studying diazotrophs,...
no nitrogenfixation can occur. In contrast, many popular sources, permaculture publications in particular, claim that Gleditsia does fix nitrogen but...
Macmillan. pp. 32–34, 40. ISBN 0-333-26820-2. Deacon J. "The Nitrogen cycle and Nitrogenfixation". Institute of Cell and Molecular Biology, The University...
microorganisms in the soil, and serve many important purposes, including nitrogenfixation. Some bacteria can colonize minerals in the soil and help influence...
Nitrogen fixation by industrial processes like the Frank–Caro process (1895–1899) and Haber–Bosch process (1908–1913) eased this shortage of nitrogen compounds...
chlorophyll. Nitrogenfixation contributes nitrogen to the plant and to the soil surrounding the plant's roots. Mimosa pudica's ability to fix nitrogen may have...
almost half of the nitrogenfixation in marine systems globally. Trichodesmium is the only known diazotroph able to fix nitrogen in daylight under aerobic...
hazardous substance. Ammonia is produced biologically in a process called nitrogenfixation, but even more is generated industrially by the Haber process. The...
reverse tricarboxylic acid cycle to perform carbon fixation. They are also mixotrophs and reduce nitrogen. Green sulfur bacteria are gram-negative rod or...
marine algae Braarudosphaera bigelowii. It plays a crucial role in nitrogenfixation, a process previously thought to be exclusive to bacteria and archaea...
which is a step in the process of nitrogenfixation. Nitrogenfixation is required for all forms of life, with nitrogen being essential for the biosynthesis...
process chemical Fixation in Canadian copyright law, a concept in Canadian copyright law Nitrogenfixation, a process by which nitrogen is converted from...
bacteria such as rhizobia, that carry out biological nitrogenfixation, in which atmospheric nitrogen (N2) is converted into ammonium (NH+ 4); and with mycorrhizal...
along the filaments. Heterocyst cells are terminally specialized for nitrogenfixation. The interior of these cells is micro-oxic as a result of increased...
fix nitrogen. Nitrogenfixation is an important part of the nitrogen cycle. Plants cannot use atmospheric nitrogen (N2); they must use nitrogen compounds...
genes are genes encoding enzymes involved in the fixation of atmospheric nitrogen into a form of nitrogen available to living organisms. The primary enzyme...
plant. Biofertilizers add nutrients through the natural processes of nitrogenfixation, solubilizing phosphorus, and stimulating plant growth through the...
within a species that can fix nitrogen there may be strains that do not. Fixation is shut off when other sources of nitrogen are available, and, for many...
Nitrogenfixation is one of the most beneficial processes performed by rhizobacteria. Nitrogen is a vital nutrient to plants and gaseous nitrogen (N2)...
nitrogen enables lichen to live in nutrient-poor environments. Lichen can also extract nitrogen from the rocks on which they grow. Nitrogenfixation,...
industrial nitrogenfixation and create chemical nitrogen fertilizer, most nitrogen introduced to ecosystems arose through biological nitrogenfixation. Some...
between legumes and their nitrogen-fixing partners to provide the nitrogen needed by these plants for growth. Nitrogenfixation can be found distributed...
(HNO3), one of several chemical processes generally referred to as nitrogenfixation. The resultant nitric acid was then used as a source of nitrate (NO3−)...
Abiological nitrogenfixation describes chemical processes that fix (react with) N2, usually with the goal of generating ammonia. The dominant technology...
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