Growth Recovery on Glucose under Aerobic Conditions of an <i>Escherichia coli</i> Strain Carrying a Phosphoenolpyruvate:Carbohydrate Phosphotransferase System Deletion by Inactivating <i>arcA</i> and Overexpressing the Genes Coding for Glucokinase and Galactose Permease

Abstract

In <i>Escherichia coli</i> the phosphotransferase system (PTS) consumes one molecule of phosphoenolpyruvate (PEP) to phosphorylate each molecule of internalized glucose. PEP bioavailability into the aromatic pathway can be increased by inactivating the PTS. However, the lack of the PTS results in decreased glucose transport and growth rates. To overcome such drawbacks in a PTS<sup>–</sup> strain and reconstitute rapid growth on glucose phenotype (Glc<sup>+</sup>), the <i>glk</i> and <i>galP</i> genes were cloned into a plasmid and the <i>arcA</i> gene was inactivated. Simultaneous overexpression of <i>glk</i> and <i>galP</i> increased the growth rate and regenerated a Glc<sup>+</sup> phenotype. However, the highest growth rate was obtained when <i>glk</i> and <i>galP</i> were overexpressed in the <i>arcA</i><sup>–</sup> background. These results indicated that the <i>arcA</i> mutation enhanced glycolytic and respiratory capacities of the engineered strain.