Glucose-Stimulated Kinetic Model for the Selection of β-glucosidase for Industrial Processes

Efficient cellulose hydrolysis for bioethanol production is limited by its end product glucose as it inhibits β-glucosidases, the final enzyme in the multi-enzyme hydrolysis. Therefore, a glucose tolerant β-glucosidase with improved activity at high glucose concentrations is essential to overcome this product inhibition. Although a variety of such β-glucosidases have been identified or engineered, a kinetic model that can compare their performance under industrially relevant conditions is valuable for optimizing enzyme selection. In this study, a glucose-stimulated kinetic model was developed by extending an existing activation model to incorporate glucose inhibition effects. The model response was evaluated using previously reported β-glucosidase hydrolysis data of p-nitrophenyl-β-D-glucopyranoside (pNP-Glu). The resulting kinetic parameters, including glucose inhibition constants and maximum specific activity provide a quantitative framework for selecting suitable β-glucosidases for industrial bioethanol production.