Corynebacterium glutamicum is particularly known for its potentiality in succinate production. We engineered C. glutamicum for the production of succinate. To enhance C-C carboxylation efficiency， chromosomal integration of the pyruvate carboxylase gene pyc resulted in strain NC-4. To increase intracellular NADH pools， the pntAB gene from Escherichia coli， encoding for transhydrogenase， was chromosomally integrated into NC-4， leading to strain NC-5. Furthermore， we deleted pgi gene in strain NC-5 to redirect carbon flux to the pentose phosphate pathway (PPP). To solve the drastic reduction of PTS-mediated glucose uptake， the ptsG gene from C. glutamicum， encoding for the glucose-specific transp... More
Corynebacterium glutamicum is particularly known for its potentiality in succinate production. We engineered C. glutamicum for the production of succinate. To enhance C-C carboxylation efficiency， chromosomal integration of the pyruvate carboxylase gene pyc resulted in strain NC-4. To increase intracellular NADH pools， the pntAB gene from Escherichia coli， encoding for transhydrogenase， was chromosomally integrated into NC-4， leading to strain NC-5. Furthermore， we deleted pgi gene in strain NC-5 to redirect carbon flux to the pentose phosphate pathway (PPP). To solve the drastic reduction of PTS-mediated glucose uptake， the ptsG gene from C. glutamicum， encoding for the glucose-specific transporter， was chromosomally integrated into pgi-deficient strain resulted in strain NC-6. In anaerobic batch fermentation， the production of succinate in pntAB-overexpressing strain NC-5 increased by 14% and a product yield of 1.22 mol/mol was obtained. In anaerobic fed-batch process， succinic acid concentration reached 856 mM by NC-6. The yields of succinate from glucose were 1.37 mol/mol accompanied by a very low level of by-products. Activating PPP and transhydrogenase in combination led to a succinate yield of 1.37 mol/mol， suggesting that they exhibited a synergistic effect for improving succinate yield.
