Production of Vitamin B12 and Labeled Vitamin B12 by Streptomyces griseus

In this study, the production of labeled vitamin B12 with one strain of actinomycet in a novel synthetic medium by batch fermentation method was investigated. After releasing vitamin B12 from microbial cells, the solution containing cobalamin analogues was fixed on amberlite XAD-4 exchanger and eluted by various solutions. Vitamin B12 in the collected fractions were measured by HPLC method and also in order to confirm the existence of cobalamin compounds in the samples, TLC technique was used. In the optimal conditions, production of vitamin B12 by this microorganism was 1456µg/l. The best recoveries of vitamin B12 from the column were obtained when the column was eluted by ethanol followed by acetone. The Rf values for cyanocobalamin and methylcobalamin, produced by this microorganism were the same as the standard values of Rf. The desorption of labeled vitamine B12 was carried out by different eluants, including acetone, ethanol (absolute), ethanol 25% and deionized water. The activity of labeled vitamin B12 was 8.55, 6.90, 0.79, 5.75 Bq/ml, respectively. Therefore, the total specific activity of 21.99Bq/ml was obtained for labeled vitamin B12.