The Effect of Glyoxylate Shunt Inactivation on Biosynthesis of Adipic Acid through Inverted Fatty Acid β-Oxidation by Escherichia coli Strains

Abstract

Using Escherichia coli MG1655 lacIQ, ∆ackA-pta, ∆poxB, ∆ldhA, ∆adhE, ∆fadE, PL-SDφ10-atoB, Ptrc-ideal-4-SDφ10-fadB, PL-SDφ10-tesB, ∆yciA as a core strain, derivatives capable of synthesizing adipic acid from glucose through the inverted fatty acid β-oxidation pathway were obtained. Biosynthesis of the target compound by recombinants was ensured by the primary condensation of acetyl-CoA and succinyl-CoA by 3-oxoacyl-CoA thiolase PaaJ and the catalysis of the final reaction of the cycle by acyl-CoA dehydrogenases FadE and FabI. Deletion in the strains of sucCD genes encoding components of succinyl-CoA synthase did not increase the relative intracellular availability of succinyl-CoA for target biosynthetic reactions and did not lead to an increase in adipic acid accumulation by the recombinants. The secretion of succinic and malic acids by the strains with an impaired tricarboxylic acid cycle remained almost unchanged, indicating the activity in the cells of glyoxylate shunt reactions that compete with the cycle reactions for isocitrate, required for succinyl-CoA formation. When isocitrate lyase, malate synthases A and G, and bifunctional kinase/phosphatase of isocitrate dehydrogenase were inactivated in strains due to deletion of the aceBAK operon genes and glcB, adipic acid synthesis by recombinants increased three-fold and reached 0.33 mM.