Biological Nitrogen Fixation: Forms and Regulating Factors

Nitrogen (N2) fixation is the basis of the global N cycle. Therefore, it is not surprising that the ability to fix atmospheric N2 evolved in the “primeval soup” and is deeply rooted in the evolutionary tree of life. Despite this, nitrogenase remains an enzyme exclusive to prokaryotes; no eukaryote has been described that can fix N2 except through a symbiotic relationship.