The issue of bioprocess dynamical modelling is addressed in the situation where measurements of extracellular species are the only available data besides measurements of the biomass itself. This question is investigated under the assumption that a metabolic network connecting the extracellular species is available. A metabolic flux analysis is first performed in order to test the consistency of the metabolic network. The elementary flux modes are computed and translated into a set of macro-reactions connecting the extracellular substrates and products. Then a dynamical model, compatible with the underlying metabolic network, is build on the basis of these macro-reactions. The approach is illustrated with the example of CHO cells cultivated in stirred flasks on a serum-free medium. (C) 2004 Elsevier Ltd. All rights reserved.