Optimization of biosynthesis of butyric acid from glucose through the inverted fatty acid β-oxidation pathway by recombinant Escherichia coli strains

The biosynthesis of butyric acid from glucose though the inverted fatty acid β-oxidation by recombinant Escherichia coli strains was optimized. The increased yield of the target compound was achieved resulting from the plasmid expression of atoB, fadB and fadE/fabI genes in the core strain MG∆4 P_L-tesB ΔyciA (MG1655 ∆ackA-pta, ∆poxB, ∆ldhA, ∆adhE, P_L-SD_j10-tesB, ∆yciA). The positive effect of enforced ATP hydrolysis on microaerobic conversion of carbohydrate substrate to the final product by the recombinants was demonstrated. Activation of the futile cycle of pyruvate-phosphoenolpyruvate-pyruvate, due to the increased expression of the ppsA gene, ensured a marked increase in glucose consumption by the recombinants and led to an increase in the molar yield of butyric acid up to 39.5%. When the components of the H⁺-ATP synthase complex were uncoupled resulting from the deletion of atpFH genes, the molar yield of butyric acid from glucose demonstrated by the strain forming butyryl-CoA by the action of enoyl-ACP reductase FabI reached 46%.