KINETIC MODELING OF PURE CELLULASES INVOLVED IN ENZYMATIC HYDROLYSIS OF CELLULOSE

摘要

The enzymatic hydrolysis of cellulose is still considered as a main limiting step of the biologicalproduction of biofuels from lignocellulosic biomass. This step involves the action of three types of cellulosedegrading enzymes acting in a synergic way: Endoglucanases, Cellobiohydrolases and β-glucosidases. Thisenzymatic cocktail, usually secreted by Trichoderma reesei at industrial scale, was already well studied andmodelling the hydrolysis kinetic has been investigated. However, most of the models are empirical and few of themdistinguish the kinetic activity of each enzyme. This article provides a new way to design a functional kinetic modeldissociating the activity of β-glucosidase as a final homogeneous reaction and the hydrolysis of cellulose bycellobiohydrolases in a heterogeneous phase. The predictive model combines a Michaelis-Menten (M-M) model forthe β-glucosidase action and a model based on Langmuir assumptions to describe the processive activity on solidsubstrate performed by cellobiohydrolases. Influences of temperature, enzyme and substrate concentration as well asinfluence of high contents of glucose have been studied and the suggested kinetic model allows a good prediction ofall the experimental data.