Kinetics of Bioethanol Production from Lactose Converted by Kluyveromyces Marxianus

A kinetic model for ethanol fermentation of lactose using yeast Kluyveromyces marxianus DSMZ 5422 is proposed. The model consists of a set of differential equations which account for substrate consumption, ethanol production and biomass production. In the model, it is assumed that alcoholic fermentation is inhibited by ethanol itself and that a different metabolic pathway is set at certain ethanol concentrations. Furthermore, lactose consumption is hypothesized to be associated to biomass growth. The model proposed is able to correctly describe lactose consumption and ethanol production. Also the main trend of biomass variation is satisfactorily correlated. The model with the set of the regression parameters is validated for its predictive ability in a larger scale batch reactor experiment.