Manipulating pyruvate to acetyl-CoA conversion in Escherichia coli for anaerobic succinate biosynthesis from glucose with the yield close to the stoichiometric maximum.

Efficient succinate production in Escherichia coli is attained during anaerobic glucose fermentation in biosynthetic processes combining the reductive branch of the TCA cycle and the glyoxylate bypass. Pyruvate dehydrogenase (PDH) or pyruvate formate lyase (PFL) serves in E. coli as a source of acetyl-CoA, a substrate for the glyoxylate bypass.

[Recombinant Escherichia coli strains deficient in mixed acid fermentation pathways and capable of rapid aerobic growth on glucose with a reduced Crabtree effect].

In this study, we constructed and characterized Escherichia coli strains deficient for mixed acid fermentation pathways, which are capable of rapid aerobic growth on glucose without pronounced bacterial Crabtree effect. The main pathways of production of acetic and lactic acids and ethanol in these strains were inactivated by a deletion of the ackA, pta, poxB, IdhA, and adhEgenes. The phosphoenolpyruvate-dependent phosphotransferase system of glucose transport and phosphorylation was inactivated in the strains by a deletion of the ptsG gene.

Comparison of different approaches to activate the glyoxylate bypass in Escherichia coli K-12 for succinate biosynthesis during dual-phase fermentation in minimal glucose media.

Two different approaches to activate the glyoxylate bypass in model Escherichia coli K-12 strains for succinate biosynthesis during dual-phase fermentation in minimal glucose media were examined. Inactivation of IclR and FadR, the transcriptional regulators of the aceBAK operon, were insufficient for the involvement of the glyoxylate bypass in anaerobic succinate biosynthesis by strains grown aerobically under glucose-abundant conditions. In contrast, the strains that constitutively expressed the aceEF-lpdA operon coding for the pyruvate dehydrogenase complex could partially synthesise succinate anaerobically via the glyoxylate bypass, even in the presence of intact regulators.

[1-butanol synthesis by Escherichia coli cells through butyryl-CoA formation by heterologous enzymes of clostridia and native enzymes of fatty acid beta-oxidation].

Anaerobic biosynthesis of 1-butanol from glucose is investigated in recombinant Escherichia coli strains which form butyryl-CoA using the heterologous enzyme complex of clostridia or as a result of a reversal in the action of native enzymes of the fatty acid beta-oxidation pathway. It was revealed that when the basic pathways of acetic and lactic acid formation are inactivated due to deletions in the ackA, pta, poxB, and ldhA genes, the efficiency of butyryl-CoA biosynthesis and its reduced product, i.e.

[Anaerobic synthesis of succinic acid by Escherichia coli strains with activated NAD+ reducing pyruvate dehydrogenase complex].

Effect of constitutive expression of the aceEF-lpdA operon genes coding for the enzymes of NAD+ reducing pyruvate dehydrogenase complex on the anaerobic production of succinic acids from glucose by recombinant Escherichia coli strains was studied. Basic producer strains were obtained by inactivation of the main pathways for synthesis of acetic and lactic acids by deletion of the genes ackA, pta, poxB, and ldhA (SGMO.1) in E.