StickstoffInkorporation

Stickstoffinkorporation refers to the process by which nitrogen atoms are incorporated into organic molecules. This is a fundamental biological process essential for life, as nitrogen is a key component of amino acids, proteins, nucleic acids, and other vital biomolecules. In biological systems, the primary source of nitrogen is atmospheric nitrogen gas (N2), which is highly stable and not directly usable by most organisms.

The critical step in making atmospheric nitrogen available to life is nitrogen fixation. This process converts N2 into ammonia (NH3) or related nitrogen compounds. Biological nitrogen fixation is primarily carried out by certain bacteria and archaea, often in symbiotic relationships with plants, such as legumes. These microorganisms possess the enzyme nitrogenase, which catalyzes the reduction of nitrogen gas.

Non-biological processes also contribute to nitrogen incorporation. For example, industrial processes like the Haber-Bosch process synthesize ammonia from nitrogen and hydrogen, which is then used to produce fertilizers. This artificial nitrogen fixation has significantly impacted agricultural productivity but also leads to environmental consequences like eutrophication.

Once nitrogen is fixed into ammonia, it can be assimilated into organic compounds through various metabolic pathways. Plants absorb fixed nitrogen from the soil, primarily as nitrate (NO3-) or ammonium (NH4+), and use it to synthesize amino acids and other nitrogen-containing molecules. Animals obtain nitrogen by consuming plants or other animals, effectively incorporating it into their own tissues. The continuous cycling of nitrogen through biological and geological processes is known as the nitrogen cycle.