Abstract
In this work, two mathematical models are proposed for a class of enzymatic hydrolysis of lignocellulosic material; one is for a quick evaluation of performance, and the other one is for behavior description. The parameters of the performance model, which is a first order linear differential equation, are used to determine the yield and the velocity of the process. On the other hand, to describe the behavior of the process, a Michaelis-Menten kinetics is recalled, where it is considered an inhibitory effect that becomes present with the reducing sugar formation. To construct and characterize model features, two different substrate-enzyme systems were performed in an automatized stirred tank reactor; along the experiments, samples were frequently taken out to obtain reducing sugar trajectories. The substrate of one of the systems was wheat straw pretreated with acid, and of the other one was the same wheat straw but pretreated with alkali; a commercial enzyme complex was used in both systems. The parameter identification was performed by minimizing squared errors between experimental trajectories and model predictions: the parameters identified for the performance model allowed a quantitative comparison between the two systems, and the descriptive model made evident the presence of an inhibitory effect along the reducing sugar formation.
