SEARCH Articles Figures Tables Bacteria biological nitrogen fixation Biological activity and nitrogen fixation Biological fixation Biological nitrogen fixation (BNF Biological nitrogen fixation energetics Biological systems nitrogen fixation Haber process biological nitrogen fixation Nitrogen biological Nitrogen fixation Nitrogen fixation biological mechanisms Nitrogen fixation molecular biology Nitrogen fixation, biological Publishing) Nitrogen, biological cycle fixation Nitrogenase biological nitrogen fixation The Enzymology of Biological Nitrogen Fixation