Continuous Culture of a Rhizobium Strain (ORS 571) Fixing Nitrogen in Culture With New and Unusual Characteristics

Abstract

ORS 571 is a fast growing Rhizobium strain which induces stem as well as root nodules on its host plant Sesbania rostrata, a tropical legume. It is the first Rhizobium strain to show nitrogen fixing growth on agar plates and in batch cultures (Dreyfus, Dommergues 1981, Elmerich et al. 1982). In contrast, other strains which fix nitrogen in culture (e.g. 32H1, CB756) are slow growers and require a reduced nitrogen source for growth. Our aim was to find out whether ORS 571 can grow continuously with N2 as the sole nitrogen source.