This paper describes how pilot-scale verification trials have improved
the accuracy of process models used in the simulation of a process fo
r the recovery and purification of an intracellular enzyme, alcohol de
hydrogenase (ADH) from packed yeast. The trials have highlighted the u
nit operations where improvements in the models are required for impro
ved accuracy. The effects of process perturbations are also used to ex
amine the robustness of the predictive models.