Performance Evaluation and Mathematical Modelling of Enzymatic Hydrolysis in 2G Bioethanol Production


Héctor Hernández-Escoto*, Javier U. Hernández-Beltrán, Ivette Navarro-Gutiérrez,
Karla Cervantes-Quintero, Salvador Hernández.

Department of Chemical Engineering, Universidad de Guanajuato – Guanajuato, Noria Alta s/n, Noria Alta, Guanajuato, Gto. 36050 México.


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.