Selective synthesis of polysaccharides byRhizobium trifolii, strain TA-1

Rhizobium trifolii strain TA-1, produces one of each of the exocellular polysaccharides EPS, CPS and β-1,2-glucans as a major product during cultivation in glutamic acid-mannitol-salts (GMS) medium at 25°. In batch culture, the major exocellular polysaccharide product was acidic exopolysaccharide (EPS) under conditions of air saturation; capsular polysaccharide (CPS) under conditions of N-limitation and moderate oxygen supply; and cyclic β-1,2-glucans at high cell density and severe oxygen limitation.