nitrogénkötést

Nitrogénkötés, often translated as nitrogen fixation, is a crucial biological and chemical process that converts atmospheric nitrogen gas (N2) into ammonia (NH3) or other nitrogenous compounds. Atmospheric nitrogen is abundant but unusable by most organisms in its diatomic form. Nitrogen fixation makes it available for biological systems, forming the basis of the nitrogen cycle.

There are several mechanisms for nitrogen fixation. Biological nitrogen fixation is carried out by specific microorganisms, primarily bacteria and archaea. These microorganisms, known as diazotrophs, possess the enzyme nitrogenase, which catalyzes the reduction of N2 to NH3. This process can occur symbiotically, as seen in the relationship between legumes and Rhizobium bacteria, or independently in free-living soil bacteria. The ammonia produced is then assimilated by plants.

Abiotic nitrogen fixation also occurs through natural and industrial processes. Lightning and volcanic activity provide energy that can break the strong triple bond of N2, leading to the formation of nitrogen oxides that eventually enter the soil as nitrates. Industrial nitrogen fixation, most notably the Haber-Bosch process, is a major source of ammonia for fertilizer production, significantly impacting global food production. However, both natural and industrial abiotic fixation can contribute to environmental issues like eutrophication when excess nitrogen enters aquatic ecosystems. The conversion of atmospheric nitrogen into a usable form is essential for life on Earth, supporting plant growth and protein synthesis.