Effect of chemical and microbial vitamin B12 analogues on production of vitamin B12

Strain improvement by genetic manipulation or optimization of fermentation conditions for overproduction of vitamin B12 has a drawback due to feed back inhibition. To resist the feed back inhibition by analogues of vitamin B12 in Propionibacterium freudenrechii subsps. shermanii (OLP-5), we have tested with microbially separated B12 analogues from three different strains. Microbial analogues were differentiated from commercially available vitamin B12 by high pressure liquid chromatography and spectrophotometric method. An analogue isolated from NRRL-B-4327 was shown to increase vitamin B12 concentration from 18.53 ± 0.15 to 31.67 ± 0.58 mg/l in OLP-5 strain. The presence of chemical analogue (ICH2 Co(DH)2 (H2Py)4) increased vitamin B12 production from 16.13 ± 0.15 to 18.53 ± 0.15 mg/l in OLP-5. These findings revealed that addition of B12 analogues in fermentation media have developed strain resistance to feed back inhibition by vitamin B12.