Selection of microorganisms producing vitamin B12 from local (Saudi)‎ isolates

الملخص EN

Forty-six bacterial strains were highly varied in their efficiency to produce cell biomass and vitamin BI2.

Propionibacterium freudenreichii ATCC 6207 and two local bacterial isolates (Streptomyces S184 and Methylomonas methanica 14B-16 were the most efficient strains.

Productivity of vitamin B12 was affected by culturing methods (shake and static), and growth phases.

The highest Vitamin B ^productivity was observed in shake culture of P.

freudenreichii (170.2 u.g/100 ml culture and 68.1 |xgl/100 mg biomass dry wt.).

This strain also showed a positive correlation between the amount of vitamin and elapsing of time.

Other bacterial strains gave amounts of Vit.

B12 ranging from 9.12 to 35.6 u.g/100 ml culture and from 1.19 to 43.6 u.g/100 ml dry wt.

biomass.

The most efficient strains also showed a high productivity at early stage of growth in shake culture.