Production of Glyoxylate from Glucose in Engineered Escherichia coli

Abstract

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.

Fine-Tuning the Expression of the Glycolate Biosynthetic Pathway in Escherichia coli Using Synthetic Promoters

“…These microorganisms utilize the naturally occurring glyoxylate shunt, including isocitrate lyase (aceA), isocitrate dehydrogenase kinase/phosphatase (aceK) and glyoxylate reductase (ycdW). Notably, E. coli is favored for glycolate production due to its rapid growth, well-established biological background and mature gene editing tools [8]. In recent years, several pathways have been designed for improving glycolate production from glucose or other substrates, such as D-xylose, ethanol, L-arabinose, glycerol, acetate, and formaldehyde.…”