Impacts of Sodium Citrate on Metabolic Flux Distributions of L-Valine Fermentation

The effect of sodium citrate on the metabolic flux distributions in the middle and late periods of L-valine production by Corynebacterium glutamicum XV0505 was obtained. It was shown that when sodium citrate (2.0 g/L) was added into the initial fermentation culture medium, the metabolic flux of Embden-Meyerhof-Parnas (EMP) route decreased from 96.43 to 91.13, and the metabolic flux of Hexose Monophophate (HMP) route increased from 3.56 to 8.87, and the metabolic flux flowing to L-alanine and acetate was decreased by 21.1% and 32.4%, respectively. Meanwhile, the metabolic flux of biosynthesis route of L-valine was increased by 10.74%. Therefore, sodium citrate can change the metabolic flux distribution in the key nodes of biosynthesis route of L-valine, decrease the generation of byproducts, and increase the metabolic flux in the biosynthesis route of L-valine.