Modelling of enzyme kinetics: cellulose enzymatic hydrolysis case

Authors:

• Magdalena Olkiewicz,
• Bartosz Tylkowski,
• Josep M. Montornés,
• Ricard Garcia-Valls,
• Iwona Ewa Gulaczyk

Abstract

nzymes as industrial biocatalysts offer numerous advantages over tradi-tional chemical processes resulting on improvements in process economy and envi-ronmental sustainability. Because enzymes are extensively used in different industrialareas, the enzyme kinetics is an important factor for industry as it is able to estimate theextent of substrate conversion under known conditions and evaluate reactor perfor-mance. Furthermore, kinetic modelling is useful in the analysis, prediction, andoptimization of an enzymatic process. Thus, kinetic modelling is a powerful tool forbiochemical reaction engineering. In addition to the aforementioned, in the industrialtechnology, modelling together with simulation play a key role because they help tounderstand how a system behaves under specific conditions, and thus they allowsaving on costs and lead times. Enzymatic conversion of renewable cellulosic biomassinto biofuels is at the heart of advanced bioethanol production. In the production ofbioethanol from cellulosic biomass, enzymatic hydrolysis of cellulose to fermentablesugars accounts for a large portion (∼30%) of the total production costs. Therefore, athorough understanding of enzymatic hydrolysis is necessary to create a robust modelwhich helps designing optimal conditions and economical system. Nevertheless, it is achallenging task because cellulose is a highly complex substrate and its enzymatichydrolysis is heterogeneous in nature, and thus the whole process of cellulose con-version to glucose involves more steps than classical enzyme kinetics. This chapterdescribes the bases of enzyme kinetic modelling, focussing on Michaelis-Menten ki-netics, and presents the models classification based on the fundamental approach andmethodology used. Furthermore, the modelling of cellulose enzymatic hydrolysis isdescribed, also reviewing some model examples developed for cellulose hydrolysisover the years. Finally, the application of enzyme kinetics modelling in food, phar-maceutical and bioethanol industry is presented