Metabolic analysis of Escherichia coli in the presence and absence of the carboxylating enzymes phosphoenolpyruvate carboxylase and pyruvate carboxylase

Article Abstract:

Escherichia coli and its metabolic analysis in the presence and absence of two carboxylating enzymes are discussed. The enzymes are phosphoenolpyruvate carboxylase (PPC) and pyruvate carboxylase (PYC). Results indicate that when PYC or PPC is expressed, the metabolic network adapts by changing the flux to lactate and the molar ratio of ethanol-to-acetate formation. That is based on the important position of pyruvate at the juncture of NADH-generating pathways and NADH-dissimilating branches.

United States, Physiological aspects, Bacterial genetics, Microbial enzymes

Overflow metabolism in Escherichia coli during steady-state growth: Transcriptional regulation and effect of the redox ratio

Article Abstract:

The role of the NADH/NAD ratio (redox ratio) in overflow metabolism is examined and the redox ratio in Escherichia coli is modulated through the expression of Streptococcus pneumoniae (water-forming) NADH oxidase. The results provide insights into new regulatory mechanisms prevalent at reduced NADH/NAD ratios, as well as for designing more efficient bioprocesses.

Microbial metabolism, Genetic regulation, Glucose, Chemical properties, Dextrose

Homolactate fermentation by metabolically engineered Escherichia coli strains

Article Abstract:

The homofermentative production of lactate in Escherichia coli strains containing mutations in the aceEF, pfl, paxB, and pps genes are described, which have encoded the pyruvate dehydrogenase complex, pyruvate formate lyase, pyruvate oxidase, and phosphoenolpyruvate synthase, respectively. The advantages of this approach for lactate production include simplicity of fermentation conditions and nutritional requirements.

Fermentation, Report