Nitrogen-fixing cyanobacteria and their associations with eukaryotic plants

Abstract The cyanobacteria (blue-green algae) are organisms which—using energy from sunlight, water as a source of reductant, and in the presence of simple inorganic salts—can convert nitrogen and carbon dioxide from the atmosphere into cell protein. Under certain conditions they also evolve hydrogen. This reviews considers ways in which cyanobacteria are organised to carry out these processes and the possibilities for turning them to practical use.