Production of vitamin B6 in Rhizobium

The production of vitamin B 6 was studied in about 1,590 bacterial isolates from soil, and an isolate, 28-21, identified as Rhizobium leguminosarum was obtained as a vitamin B 6 high producer. Then, the production of vitamin B 6 by commercially available Rhizobium strains was examined, and many of the tested strains excreted large amounts of vitamin B 6 into the culture broth. The best producer of vitamin B 6 was R. meliloti IFO 14782, which produced 51 mg per liter. Media study for the vitamin B 6 production was done with R. meliloti IFO 14782; the strain was able to excrete 84 mg of vitamin B 6 per liter, 79 mg per liter of which was pyridoxol.