Enzymatic hydrolysis of cellulose part II: Population balance modelling of hydrolysis by exoglucanase and universal kinetic model

In this work a population balance based kinetic model for the action of exoglucanase has been developed. A new mechanism for hydrolysis of cellulose by exoglucanase is proposed in which a bond breakage is a function of position in the chain as well as the susceptibility to enzymatic attack. Having developed the model for the action of endoglucanase in part I of this work, here a mechanistic model for the action of exoglucanase and then a holistic model considering all the major steps involved in enzymatic hydrolysis has been proposed. Having established and validated the models for the action of endo- and exoglucanase, a universal model for the cellulose hydrolysis at the surface and inside the particle have been developed. For the unknown parameters in the universal models, an experimental procedure to find the parameters in the holistic model has been proposed. It is believed that the universal kinetic model can be applied to almost any cellulose–cellulase system and once parameters for different systems are available, due to characteristic nature of the model, it would be possible to optimise the system under different conditions.

► Degree of polymerisation is influential factor in enzymatic hydrolysis.
► Population balanced modelling of Enzymatic hydrolysis can take this into account.
► Endo- and Exoglucanase should be treated completely differently in development of kinetic models.