[Effect of organic substances on the growth and cobalamin genesis of Achromobacter cobalamini]

Corn steep and molasses were shown to stimulate cobalaminogenesis in Achromobacter cobalamini. Their concentrations optimal for the culture growth and vitamin B12 synthesis were found. Corn steep at a concentration of 2% accelerated the growth. The biomass yield and the content of B12 were maximal after 48 h of fermentation. In the medium with molasses, the growth was stimulated at 1% of molasses, and the vitamin biosynthesis at 5%. When 5% of molasses was added into the mineral medium, the rate of biosynthesis increased by a factor of 5 to 7 as compared to the control. A 5% aqueous solution of molasses containing 1.1 g/l of potassium phosphates produced the same effect as an addition of molasses to the complete mineral medium.