Nitrogenase activity of Rhizobium sp. strains in pure culture in relation to extracellular polysaccharide composition and antigenic affinity.

Five strains of slow-growing Rhizobium sp. (strains CB756, 32HI, CB562, CB627 and QA549) out of seventy examined developed appreciable nitrogenase activity in pure culture. CB756 and 32HI were serologically indistinguishable and each produced 6-deoxy-L-talose as a major component of its extracellular polysaccharide. They did not share these properties with CB562, CB627 or QA549.