The Production of Vitamin B₁₂‐Active Substances by Marine Bacteria

Abstract

The production of members of the vitamin‐B 12 family of compounds by 34 marine bacteria that were grown in a B 12 ‐deficient medium was assayed. Using aliquots of the same bacterial culture, 70 per cent and 30 per cent had activity for the assay organisms Escherichia coli 113‐3 and Euglena gracilis, z strain, respectively. Using the Euglena assay, no apparent relation was evident between the activities of the cell residues or corresponding supernatants and the relative amount of growth of each culture. However, of the 24 bacterial cultures tested, the supernatants of 42 per cent had activity, whereas the corresponding cell residues of 63 per cent had activity.