Improved large-scale production of vitamin B12 by Pseudomonas denitrificans with betaine feeding.

The strategy of betaine control for vitamin B12 large-scale fermentation by Pseudomonas denitrificans was investigated in this paper. The results obtained in shake-flask experiments demonstrated that betaine could greatly stimulate vitamin B12 biosynthesis but had an inhibition to cell growth. Based on the influence of betaine on the fermentation of P. denitrificans, betaine feeding was a beneficial strategy to solve the inconsistency between cell growth and vitamin B12 production. As a result, an effective and economical strategy of betaine feeding was established for vitamin B12 fermentation in 120-m3 fermenter, in which betaine was continuously fed to maintain betaine concentration of the broth at the range of 5-7g/l during 50-140h of fermentation.