Production of Succinate from Acetate by Metabolically Engineered Escherichia coli.

Acetate, a major component of industrial biological wastewater and of lignocellulosic biomass hydrolysate, could potentially be a less costly alternative carbon source. Here we engineered Escherichia coli MG1655 strain for succinate production from acetate as the sole carbon source. Strategies of metabolic engineering included the blockage of the TCA cycle, redirection of the gluconeogenesis pathway, and enhancement of the glyoxylate shunt. The engineered strain MG03 featuring the deletion of genes: succinate dehydrogenase (sdhAB), isocitrate lyase regulator (iclR), and malic enzymes (maeB) accumulated 6.86 mM of succinate in 72 h. MG03(pTrc99a-gltA) overexpressing citrate synthase (gltA) accumulated 16.45 mM of succinate and the yield reached 0.46 mol/mol, about 92% of the maximum theoretical yield. Resting-cell was adopted for the conversion of acetate to succinate, and the highest concentration of succinate achieved 61.7 mM.