Cobalt Salt-Induced Increase in Vitamin B12 Production by Escherichia coli in Anaerobic Fermentation

Abstract

Vitamin B12 producing E. coli was isolated by anaerobic fermentation. By means of biological quantification with E. coli mutant strain 215, the bacterial production of vitamin B12 in the presence of cobalt chloride (CoCl2 • 2H2O) or cobalt sulfate (CoSO4 • 7H2O) was studied in the E. coli cells harvested from anaerobic fermentation, using cultured cells (dry and wet) and concentrated culture. A significant increase was found in vitamin B12 content between the dry cells treated with cobalt chloride (8mg/l) or cobalt sulfate (10mg/l) and the control cells not treated with cobalt salts (p<0.01). The production of vitamin B12 was increased by 4.5-6.2 times via the addition of cobalt salts, compared to that without the addition of these agents.