nitrogen fixation is a process in which nitrogen (n2) in the atmosphere is converted into ammonium (nh4+). atmospheric nitrogen or molecular nitrogen (n2) is relatively inert: it does not easily react with other chemicals to form new compounds. the fixation process frees up the nitrogen atoms from their triply bonded diatomic form, nâ¡n, to be used in other ways. nitrogen fixation, natural and synthetic, is essential for all forms of life because nitrogen is required to biosynthesize basic building blocks of plants, animals and other life forms, e.g., nucleotides for dna and rna and amino acids for proteins. therefore, nitrogen fixation is essential for agriculture and the manufacture of fertilizer. it is also an important process in the manufacture of explosives (e.g. gunpowder, dynamite, tnt, etc.). nitrogen fixation occurs naturally in the air by means of lightning.http://journals.ametsoc.org/doi/abs/10.1175/1520-0469%281980%29037%3c0179%3aanfbl%3e2.0.co%3b2 nitrogen fixation also refers to other biological conversions of nitrogen, such as its conversion to nitrogen dioxide. all biological nitrogen fixation is done by way of nitrogenase metalo-enzymes which contain iron, molybdenum, or vanadium. microorganisms that can fix nitrogen are prokaryotes (both bacteria and archaea, distributed throughout their respective kingdoms) called diazotrophs. some higher plants, and some animals (termites), have formed associations (symbiosis) with diazotrophs. == biological nitrogen fixation ==  biological nitrogen fixation was discovered by the german agronomist hermann hellriegel and dutch microbiologist martinus beijerinck. biological nitrogen fixation (bnf) occurs when atmospheric nitrogen is converted to ammonia by an enzyme called nitrogenase. the reaction for bnf is: : n2 + 8 h+ + 8 eâ â 2 nh3 + h2 the process is coupled to the hydrolysis of 16 equivalents of atp and is accompanied by the co-formation of one molecule of h2. the conversion of n2 into ammonia occurs at a cluster called femoco, an abbreviation for the iron-molybdenum cofactor. the mechanism proceeds via a series of protonation and reduction steps wherein the femoco active site hydrogenates the n2 substrate.hoffman, b. m., lukoyanov, d., dean, d. r., seefeldt, l. c., "nitrogenase: a draft mechanism", acc. chem. res. 2013, volume 46, 587. {{
Metabolism Nitrogen_metabolism Plant_physiology Soil_biology