ABSTRACT
Proteins and nucleic acids, both of which contain Nitrogen (N), are fundamental to all life on Earth. The Haber–Bosch process for atmospheric N fixation has had consequences for humans and the Earth almost as profound as those of any other scientific innovation of the twentieth century. The consequence, unforeseen by Haber and Bosch, has been disruption of the N cycle on a global scale. Some microbes have nitrogenases with different transition metals that function at different temperatures. The natural cycling of N on Earth is therefore particularly dependent on biological activity, with plants being the conduit for N into most unmanaged and managed terrestrial ecosystems. Artificially fixed N helped to fuel the population boom of the twentieth century because, remarkably, despite enormous population growth it helped to increase food production per capita. Nitrogenase activity also produces H2, and the elucidation of the operation of this complex might also have an impact on biohydrogen production.
