The aim of this work was to study the performance of an ethanologenic E. coli strain in batch and continuous cultures. A medium, that simulated the macromolecular composition of a hemicellulosic hydrolyzate (mineral medium supplemented with xylose, glucose and acetate: 42.5, 7.5 and 2.0 g/L, respectively), was used. Results using the ethanologenic E. coli strain MG1655 ΔldhA, ΔpflB, ΔadhE, ΔfrdA, PpflB::pdc_Zm-adhA_Zm, and not aerated batch cultures shown that xylose and glucose were co-utilized with a volumetric productivity of 0.7 g_EtOH /l h, and a conversion yield of sugars into ethanol of 93% of the theoretical was obtained. Instead of inhibition, the acetate used stimulated cellular growth and ethanol production. It is suggested that the genetic background of the strain stimulated the partial consumption of acetate to replenish part of the acetil-CoA pool, which is reduced in the strain due to the interruption of the pflB gene. Continuous cultures performed with the same media and conditions of the batch fermentations, and with dilution rates (D) in the range of 0.05-0.25 h^-1 showed reduced biomass and ethanol concentrations, and incomplete sugar consumption. However, conversion yield of the consumed sugar was 80% of the theoretical and maximum volumetric productivity (0.64 g_EtOH /l h) was found at a D of 0.1 h^-1. The value of the non-growth associated constant from the Luedeking-Piret model, indicates that it is necessary to maintain growth rates near zero or to use cascade continuous cultures to promote total sugar utilization and higher ethanol concentrations.