Résumé : Genetic manipulation has allowed the development of a strain of Escherichia coli with a higher biomass yield. The objective of this work is to understand the effect of the genetic manipulation at a macroscopic level, i.e. to derive a dynamic model of the evolution of the main macroscopic components of interest (substrate, biomass and products), and to compare it with a model of the wild type strain. After parameter estimation based on extensive experimental data from cultivation in batch and fed-batch, pseudo-stoichiometric coefficients and kinetic terms show that the mutant strain produces more biomass in the oxidative phase and produces less acetate per substrate consumed than the wild type strain. On the other hand, no significant difference in the maximal glucose consumption rate and the maximal critical consumption rate are found. © 2012 IFAC.