Production of vitamin B12 in an upflow anaerobic filter continuous reactor using Acetobacterium sp.

The accumulation of biofilm by Acetobacterium sp. during continuous culture in an upflow anaerobic filter (UAF) growing on methanol-formate was the result of space velocity and inlet concentrations of substrate and Co+2. To achieve good development of biofilm, a space velocity of 0.38 h(-1), inlet substrate concentrations of 125 mM of both methanol and formate, and Co+2 at 0.16 mM were required. Cell productivities in the effluent of the UAF-reactor were about 6-fold higher than in chemostat cultures (0.20 g l(-1) h(-1) for UAF and 0.035 g l(-1) h(-1) for chemostat) (previous studies), and the maximum vitamin B-12 specific concentration was 5.1 mg g cell(-1).