Production of Glyoxylate from Glucose in Engineered Escherichia coli

Glyoxylates are essential intermediates in several metabolic pathways and have a broad range of industrial applications. In this study, we propose a novel method for producing glyoxylate from glucose using engineered Escherichia coli BW25113. To direct the production of glyoxylate from glucose, malate synthase A (aceB), malate synthase G (glcB), glyoxylate carboligase (gcl), and glyoxylate/hydroxypyruvate reductase A (ycdW) genes were disrupted, and the glyoxylate shunt was reinforced in the disruptants by the overexpression of citrate synthase (gltA) and isocitrate lyase (aceA). In flask cultivation using M9 medium supplemented with 1% glucose, the disruptant E. coli BW25113 ΔaceB ΔglcB Δgcl ΔycdW produced 0.93 ± 0.17 g/L of glyoxylate. Further overexpression of gltA and aceA in the disruptant resulted in an improvement in glyoxylate production to 1.15 ± 0.02 g/L. By expressing a heterologous gene, pyc, in the engineered E. coli, the accumulation of intracellular oxaloacetate remarkably improved, leading to glyoxylate production of up to 2.42 ± 0.00 g/L with specific productivity at 4.22 ± 0.09 g/g-cell. To date, this is the highest reported titer and specific productivity of glyoxylate in E. coli.