Enhancement in VitaminB sub( 12) Production By Mutant Strains of Propionibacterium freudenreichii

In the present study vitaminB12 production was carried out with parental and mutant strains of Propionibcterium freudenreichii. Physical mutagenesis was performed by three different doses of U.V. irradiation- 200, 300 and 400erg/mm2and five different irradiation time periods were selected- 30sec, 60sec, 90sec, 120 sec and 150sec. Obtained 15 mutant strains were used to produce vitaminB12 by anaerobic and aerobic fermentation techniques at 300C, 320C and 340C. 200 erg/mm2 U.V. dose and short duration exposure haven't developed any desirable character in organism but mutants which were exposed to 400 erg/mm2 for 60 seconds developed desirable (resistant to propionic acid) character. High yield of vitmainB12 was produced at 300C by mutants of P. freudenreichii.