Kinetics of Adsorption, Desorption, and Re-Adsorption of a Commercial Endoglucanase in Lignocellulosic Suspensions

This study conducted quantitative kinetic modeling and in-situ and temporally resolved measurements of adsorption, desorption, and re-adsorption of a commercial endoglucanase in lignocellulosic suspensions.  The study defined a cellulase adsorption and desorption competition parameter, a pseudo rate of binding and desorption, binding and desorption capacity, as well as cellulase binding reversibility (a thermodynamic property) and recyclability (a engineering parameter).  The results indicate that both substrate chemical and physical structures play important roles in cellulase binding and desorption.  Binding of a commercial cellulase onto a cellulosic substrate was reversible.  Bindings to two different lignocellulosic substrates were almost irreversible.  While lignin and its structure positively affect binding capacity to substrate, they negatively affect cellulase recyclability. Collapsing of substrate pores reduced cellulose accessibility and cellulase binding capacity and increased reversibility and recyclability.  Increasing temperature and pH increase cellulase desorption and increased binding reversibility and capacity.  This study lays the foundation for developing effective cellulase recycling strategies.