Nitrogen fixation is the process by which nitrogen is taken from its natural, relatively inert molecular form (N₂) in the atmosphere and converted into nitrogen compounds (such as ammonia, nitrate and nitrogen dioxide)^[1]. Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor In Inorganic chemistry, a nitrate is a salt of Nitric acid with an Ion composed of one Nitrogen and three Oxygen atoms Nitrogen dioxide is the Chemical compound with the formula N[[Oxygen O]]2

Nitrogen fixation is performed naturally by a number of different prokaryotes, including bacteria, actinobacteria, and certain types of anaerobic bacteria. The prokaryotes (proʊˈkærioʊts singular prokaryote /proʊˈkæriət/ are a group of Organisms that lack a Cell nucleus (= karyon or any other The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have Actinobacteria or actinomycetes are a group of Gram-positive bacteria with high G+C ratio. An anaerobic organism is any Organism that does not require Oxygen for growth and may even die in its presence Microorganisms that fix nitrogen are called diazotrophs. Diazotrophs are Bacteria that fix atmospheric Nitrogen gas into a more usable form such as Ammonia. Some higher plants, and some animals (termites), have formed associations with diazotrophs. The termites are a group of Social Insects usually classified at the taxonomic rank of order Isoptera (but see also taxonomy

Nitrogen fixation also occurs as a result of non-biological processes. These include lightning, industrially through the Haber-Bosch Process, and combustion. Lightning is an atmospheric discharge of Electricity, which typically occurs during Thunderstorms and sometimes during volcanic eruptions or The Haber process, also called the Haber–Bosch process, is the Nitrogen fixation reaction of Nitrogen and Hydrogen, over an iron substrate ^[2]

Biological nitrogen fixation was discovered by the Dutch microbiologist Martinus Beijerinck. Martinus Willem Beijerinck ( March 16, 1851 - January 1, 1931) was a Dutch Microbiologist and Botanist

Contents 1 Biological nitrogen fixation 2 Non-leguminous nitrogen-fixing plants 3 Microorganisms that fix nitrogen 3.1 Nitrogen Fixation by Cyanobacteria 4 Chemical nitrogen fixation 5 References 6 See also 7 External links

Biological nitrogen fixation

Biological Nitrogen Fixation (BNF) occurs when atmospheric nitrogen is converted to ammonia by a pair of bacterial enzymes called nitrogenase. Nitrogenase ( is the Enzyme used by some organisms to fix atmospheric Nitrogen gas (N2 ^[1] The formula for BNF is:

N₂ + 8H⁺ + 8e⁻ + 16 ATP → 2NH₃ + H₂ + 16ADP + 16 P_i

Although ammonia (NH₃) is the direct product of this reaction, it is quickly protonated into ammonium (NH₄⁺). Adenosine-5'-triphosphate ( ATP) is a multifunctional Nucleotide that is most important as a " molecular currency" of intracellular Energy Adenosine diphosphate, abbreviated ADP, is a Nucleotide. It is an Ester of Pyrophosphoric acid with the Nucleoside Adenosine A phosphate, an Inorganic chemical, is a salt of Phosphoric acid. Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor In chemistry protonation is the addition of a proton ( H[[Cation +]] to an Atom, Molecule, or Ion. Ammonium is also an old name for the Siwa Oasis in western Egypt. In free-living diazotrophs, the nitrogenase-generated ammonium is assimilated into glutamate through the glutamine synthetase/glutamate synthase pathway. Glutamic acid (abbreviated as Glu or E) is one of the 20 Alpha Amino acids It is not among the human Essential amino acids Its

In most bacteria, the nitrogenase enzymes are very susceptible to destruction by oxygen (and many bacteria cease production of the enzyme in the presence of oxygen). ^[1] Low oxygen tension is achieved by different bacteria by: living in anaerobic conditions, respiring to draw down oxygen levels, or binding the oxygen with a protein such as Leghemoglobin - also spelled leghaemoglobin. The oxygen carrier leghemoglobin (also legoglobin) is a Hemoprotein found in the nitrogen-fixing root nodules of leguminous plants ^[1].

The best-known plants which contribute to nitrogen fixation in nature, are in the legume family - Fabaceae, which includes such taxa as clover, beans, alfalfa, lupines and peanuts. A legume is a Plant in the family Fabaceae (or Leguminosae or a Fruit of these specific plants Fabaceae or Leguminosae is a large and economically important family of Flowering plants which is commonly known as the legume family, pea Alsike redirects here Alsike Sweden is also a town in the Knivsta Municipality, Sweden. They contain symbiotic bacteria called rhizobia within nodules in their root systems, producing nitrogen compounds that help the plant to grow and compete with other plants. This article is about the biological phenomenon for other uses see Symbiosis (disambiguation The term symbiosis (from the Greek Rhizobia (from the Greek words rhiza = root and bios = Life are Soil bacteria that fix Nitrogen ( Diazotrophy Root nodules occur on the roots of plants that associate with Vigna bacteria. ROOT is an object-oriented program and library developed by CERN. When the plant dies, the fixed nitrogen is released, making it available to other plants and this helps to fertilize the soil^[1][3] The great majority of legumes have this association, but a few genera (e. Soil, often typeset as SOiL, is a four piece rock band from Chicago Illinois United States founded by Shaun Glass Tom Schofield Tim King and Adam Zadel g. , Styphnolobium) do not. Styphnolobium is a small genus of three or four species of small Trees and Shrubs in the subfamily Faboideae of the pea family Fabaceae In many traditional and organic farming practices, fields are rotated through various types of crops, which usually includes one consisting mainly or entirely of clover or buckwheat (family Polygonaceae), which were often referred to as "green manure", since the other natural way of adding nitrogen to the soil is via animal waste products. Polygonaceae is a family of flowering plants also known as the "knotweed family" or "smartweed family" The entire plant is often ploughed back into the field, thus not only adding more nitrogen, but also improving the soil's organic content and volume.

Non-leguminous nitrogen-fixing plants

Although by far the majority of nitrogen-fixing plants are in the legume family Fabaceae, there are a few non-leguminous plants that can also fix nitrogen. Fabaceae or Leguminosae is a large and economically important family of Flowering plants which is commonly known as the legume family, pea These plants, referred to as actinorhizal plants, consist of 22 genera of woody shrubs or trees scattered in 8 plant families. The ability to fix nitrogen is not universally present in these families. For instance, of 122 genera in the Rosaceae, only 4 genera are capable of fixing nitrogen. The Rosaceae or Rose family is a large family of Plants with about 3000-4000 species in 100-160 genera

Family: Genera

Betulaceae (Birch): Alnus (Alder)

Casuarinaceae (she-oaks):

Allocasuarina

Casuarina

Gymnostoma

Coriariaceae: Coriaria

Datiscaceae: Datisca

Elaeagnaceae (oleaster):

Elaeagnus (silverberry)

Hippophae (sea-buckthorn)

Shepherdia (buffaloberries)

Myricaceae:

Morella arborea

Myrica

Comptonia

Rhamnaceae (buckthorn):

Ceanothus

Colletia

Discaria

Kentrothamnus

Retanilla

Trevoa

Rosaceae (rose):

Cercocarpus (mountain mahogany)

Chamaebatia (mountain misery)

Purshia (bitterbrush or cliff-rose)

Dryas

There are also several nitrogen-fixing symbiotic associations that involve cyanobacteria (such as Nostoc). Betulaceae, or the Birch Family, includes six genera of Deciduous nut -bearing Trees and Shrubs including the Birches Alder is the common name of a Genus of Flowering plants ( Alnus) belonging to the Birch family (Family Betulaceae) Casuarinaceae is a family of dicotyledonous Flowering plants placed in the order Fagales, consisting of 3 or 4 genera and approximately 70 Allocasuarina is a Genus in the Flowering plant family Casuarinaceae. Casuarina is a Genus of 17 species in the family Casuarinaceae, native to Australasia, southeastern Asia, and islands of the Coriaria is the sole genus in the family Coriariaceae. It includes about 30 species of Subshrubs Shrubs and small Trees with a Coriaria is the sole genus in the family Coriariaceae. It includes about 30 species of Subshrubs Shrubs and small Trees with a Datiscaceae are a family of Dicotyledonous plants containing two species of the genus Datisca. Elaeagnaceae, the oleaster family, is a Plant family of the order Rosales comprising small Trees and Shrubs Elaeagnus ( Silverberry or Oleaster) is a genus of about 50–70 species of Flowering plants in the Elaeagnaceae. The sea-buckthorns ( Hippophae L are Deciduous Shrubs in the genus Hippophae, family Elaeagnaceae. Shepherdia ( Buffaloberries) are a genus of small shrubs which have rather bitter tasting berries native to North America. The Myricaceae is a small family of Dicotyledonous Shrubs and small Trees in the order Fagales. UserPolbot. --> Morella arborea is a species of Plant in the Myricaceae family Myrica is a genus of about 35-50 species of small Trees and Shrubs in the family Myricaceae order Fagales Comptonia is a Monotypic genus (containing only Comptonia peregrina) in the family Myricaceae, order Fagales. Rhamnaceae, the Buckthorn family is a large family of flowering Plants mostly trees Shrubs and some vines Ceanothus L is a Genus of about 50–60 species of Shrubs or small Trees in the buckthorn family Rhamnaceae. Colletia is a genus of Flowering plants in the family Rhamnaceae, with 15 to 17 species of spiny Shrubs All Species Discaria is a genus of about 12 species of Flowering plants in the family Rhamnaceae, native to temperate regions of the Southern Hemisphere The Rosaceae or Rose family is a large family of Plants with about 3000-4000 species in 100-160 genera Mountain-mahogany ( Cercocarpus) is a small genus of five or six species of Deciduous Shrubs or small Trees in the rose family ( Rosaceae The plant genus Chamaebatia includes two species of aromatic evergreen shrubs known as mountain misery. Purshia ( bitterbrush or cliff-rose) is a small genus of 5-8 species of Flowering plants in the family Rosaceae, native to western Dryas is a genus of dwarf perennial Herbaceous Plants in the Rose family Rosaceae, native to the arctic and alpine Cyanobacteria, also known as blue-green algae, blue-green bacteria or Cyanophyta, is a phylum of Bacteria that obtain their energy These include some lichens such as Lobaria and Peltigera:

• Mosquito fern (Azolla species)
• Cycads
• Gunnera

Microorganisms that fix nitrogen

• Diazotrophs
• Cyanobacteria
• Azotobacteraceae
• Rhizobia
• Frankia

Nitrogen Fixation by Cyanobacteria

Cyanobacteria inhabit nearly all illuminated environments on Earth and play key roles in the carbon and nitrogen cycle of the biosphere. Lobaria is a genus of Lichens commonly known as "lungwort" or "lung moss" because their physical shape somewhat resembles a lung Lichens of the genus Peltigera are often terricolous (growing on soil but can also occur on moss trees rocks and many other substrates in many parts of the world Azolla ( mosquito fern, duckweed fern, fairy moss, water fern) is a Genus of seven species of aquatic Azolla ( mosquito fern, duckweed fern, fairy moss, water fern) is a Genus of seven species of aquatic Cycads are a group of Seed plants characterized by a large crown of compound leaves and a stout trunk. Gunnera is a genus of Herbaceous Flowering plants some of them gigantic Diazotrophs are Bacteria that fix atmospheric Nitrogen gas into a more usable form such as Ammonia. Cyanobacteria, also known as blue-green algae, blue-green bacteria or Cyanophyta, is a phylum of Bacteria that obtain their energy The family Azotobacteraceae contains aerobic diazotrophs with two Genera Azomonas and Azotobacter, distinguished by the ability to form Cysts. Rhizobia (from the Greek words rhiza = root and bios = Life are Soil bacteria that fix Nitrogen ( Diazotrophy This article refers to the bacteria Frankia was also one of the names of the Frankish Empire. Cyanobacteria, also known as blue-green algae, blue-green bacteria or Cyanophyta, is a phylum of Bacteria that obtain their energy The nitrogen cycle is the Biogeochemical cycle that describes the transformations of Nitrogen and nitrogen-containing compounds in nature The biosphere is the broadest level of ecological study the global sum of all Ecosystems. Generally, cyanobacteria are able to utilize a variety of inorganic and organic sources of combined nitrogen, like nitrate, nitrite, ammonium, urea or some amino acids. Cyanobacteria, also known as blue-green algae, blue-green bacteria or Cyanophyta, is a phylum of Bacteria that obtain their energy In Inorganic chemistry, a nitrate is a salt of Nitric acid with an Ion composed of one Nitrogen and three Oxygen atoms The nitrite Ion is NO2− The anion is bent being Isoelectronic with O3. Ammonium is also an old name for the Siwa Oasis in western Egypt. Urea is an Organic compound with the Chemical formula ( N[[hydrogen H]]22 C[[oxygen O]] In Chemistry, an amino acid is a Molecule containing both Amine and Carboxyl Functional groups In Biochemistry, this Several cyanobacterial strains are also capable of diazotrophic growth. Diazotrophs are Bacteria that fix atmospheric Nitrogen gas into a more usable form such as Ammonia. Genome sequencing has provided a large amount of information on the genetic basis of nitrogen metabolism and its control in different cyanobacteria. The term DNA sequencing encompasses biochemical methods for determining the order of the Nucleotide bases Adenine, Guanine, Cytosine The nitrogen cycle is the Biogeochemical cycle that describes the transformations of Nitrogen and nitrogen-containing compounds in nature Comparative genomics, together with functional studies, has led to a significant advance in this field over the past years. Comparative genomics is the study of the relationship of Genome structure and function across different biological Species or strains. 2-oxoglutarate has turned out to be the central signalling molecule reflecting the carbon/nitrogen balance of cyanobacteria. Central players of nitrogen control are the global transcriptional factor NtcA, which controls the expression of many genes involved in nitrogen metabolism, as well as the P_II signalling protein, which fine-tunes cellular activities in response to changing C/N conditions. These two proteins are sensors of the cellular 2-oxoglutarate level and have been conserved in all cyanobacteria. In contrast, the adaptation to nitrogen starvation involves heterogeneous responses in different strains. ^[4]

Chemical nitrogen fixation

Nitrogen can also be artificially fixed for use in fertilizer, explosives, or in other products. Fertilizers ( also spelt fertiliser are chemical compounds given to Plants to promote growth they are usually applied either through the soil for uptake by plant The most popular method is by the Haber process. The Haber process, also called the Haber–Bosch process, is the Nitrogen fixation reaction of Nitrogen and Hydrogen, over an iron substrate This artificial fertilizer production has achieved such scale that it is now the largest source of fixed nitrogen in the Earth's ecosystem. EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 An ecosystem is a natural unit consisting of all plants animals and micro-organisms( Biotic factors in an area functioning together with all of the non-living physical (

The Haber process requires high pressures and very high temperatures and active research is committed to the development of catalyst systems that convert nitrogen to ammonia at ambient temperatures. Many compounds can react with atmospheric nitrogen under ambient conditions (eg lithium makes lithium nitride if left exposed), but the products of such reactions are not easily converted into biologically accessible nitrogen sources. After the first dinitrogen complex was discovered in 1965 based on ammonia coordinated to ruthenium ([Ru(NH₃)₅(N₂)]²⁺)^[5], research in chemical fixation focused on transition metal complexes. The term complex in Chemistry is usually used to describe molecules or ensembles formed by the combination of Ligands and metal Ions. Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor Ruthenium (ruːˈθiːniəm is a Chemical element that has the symbol Ru and Atomic number 44 Since that time a large number of transition metal compounds that contain dinitrogen as ligand have been discovered. The dinitrogen ligand can be bound either to a single metal or bridge two (or more) metals. The coordination chemistry of dinitrogen is rich and under intense study. This research may lead to new ways of using dinitrogen in synthesis and on an industrial scale.

The first example of homolytic cleavage of dinitrogen under mild conditions was published in 1995. In Chemistry, homolysis or homolytic fission is Chemical bond dissociation of a neutral Molecule generating two Free radicals That Two equivalents of a molybdenum complex reacted with one equivalent of dinitrogen, creating a triple bonded MoN complex^[6]. Molybdenum (məˈlɪbdənəm from the Greek word for the metal " Lead " is a Group 6 Chemical element with the symbol Mo Since this triple bounded complex has been used to make nitriles ^[7]. A nitrile is any Organic compound which has a - C ≡ N Functional group. The first catalytic system converting nitrogen to ammonia at room temperature and 1 atmosphere was discovered in 2003 and is based on another molybdenum compound, a proton source and a strong reducing agent. A reducing agent (also called a reductant or reducer) is the element or a compound in a Redox (reduction-oxidation reaction (see Electrochemistry ^[8][9][10] Unfortunately, the catalytic reduction only undergoes a few turnovers before the catalyst dies.

In contrast to the graphic shown above, the major product of this reaction is ammonia (NH3) and not an ammonium salt ([NH4][X]). In fact, approximately 75% of the ammonia produced can be distilled away from the reaction vessel (suggesting the ammonia is not protonated) into a vessel containing HCl as a trap. This method of trapping the NH3 was doubtlessly chosen because it makes the product easier to handle. Also, note that because only 1 equiv of Cl anion is available under catalytic conditions (via reduction of the precatalyst molbdenum chloride, shown) therefore it is unlikely that the product ammonium salt would always have this counterion.

Note also that although the dinitrogen complex is shown in brackets this species can be isolated and characterized. Here the brackets do not indicate that the intermediate is not observed.

References

See also

• Denitrification
• George Washington Carver
• Nitrification
• Nitrogen cycle
• Nitrogen deficiency
• Nitrogenase
• Birkeland-Eyde process

External links

• Nitrogen Fixation
• NITROGEN FIXATION

Denitrification is a microbially facilitated process of dissimilatory nitrate reduction that may ultimately produce molecular Nitrogen (N2 through a series of intermediate George Washington Carver (January 1864 – January 5 1943 was an African American Scientist, Botanist, Educator, and Inventor Nitrification is the biological oxidation of Ammonia with oxygen into Nitrite followed by the oxidation of these nitrites into Nitrates Degradation The nitrogen cycle is the Biogeochemical cycle that describes the transformations of Nitrogen and nitrogen-containing compounds in nature This is about nitrogen compounds in plant nutrition For shortage of nitrogen compounds in human and animal nutrition see Protein deficiency. Nitrogenase ( is the Enzyme used by some organisms to fix atmospheric Nitrogen gas (N2 The Birkeland-Eyde process was developed by Norwegian industrialist and scientist Kristian Birkeland along with his business partner Sam Eyde.

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