The Hydrogenase-Nitrogenase Relationship in a Symbiotic Cyanobacterium Isolated From Macrozamia communis L. Johnson

Abstract

The relationship between nitrogenase and hydrogenase activity in the cyanobacterial isolate from the corolloid roots of the cycad Macrozamia communis, grown both photoautotrophically and heterotrophically, has been investigated. The organism actively consumes hydrogen gas in both light and darkness in an oxygen-dependent reaction. The hydrogen consumption was substantially stimulated by light and was nickel-dependent. Nitrogenase activity was found not to be enhanced by hydrogen, either in the dark or light.