Effects of Amino Acid Precusors on Vitamin B12 Fermentation

Glutamine, threonine, glycine and methionine, crucial biosynthetic precursors for vitamin B12 production in Pseudomonas denitrifican, were fed respectively in the late fermentation phase to investigate their effects on the production of vitamin B12 by Pseudomonas denitrifican. According to the results of the singlefactor experiments, an orthogonal experimental design with three factors and three levels was performed. The results of the orthogonal experiments indicated that glutamine was the major factor affecting the cell growth and product formation. A combination of multiple amino acids could be more beneficial to vitamin B12 production. An increase of 13.1% in biomass and an increase of 46.0% in vitamin B12 production with the addition of 0.45 g/L glutamine, 0.20 g/L threonine and 0.15 g/L glycine into the fermentation broth.