Azotobacter vinelandii is Gram-negative diazotroph that can fix nitrogen while grown aerobically.

A. vinelandii is a free-living N2 fixer known to produce many phytohormones and vitamins in soils.

[4] The nitrogenase holoenzyme of A. vinelandii has been characterised by X-ray crystallography in both ADP tetrafluoroaluminate-bound[5] and MgATP-bound[6] states.

It is a genetically tractable system that is used to study nitrogen fixation.

Genetically engineered strains can produce significantly higher amounts of ammonia.