Comparison of the interactions between fungal cellulases from different origins and cellulose nanocrystal substrates with different polymorphs

Abstract

To identify the interactions between the carbohydrate-binding module (CBM) of fungal cellulases and the surface of cellulose crystalline regions, the interactions between four fungal cellulases from different origins and cellulose nanocrystal substrates with polymorphs of cellulose I, II, and the hybrid I/II, were measured by a quartz crystal microbalance with dissipation technique and compared in this investigation. The experiments of cellulase adsorption/desorption on substrates were conducted at 15 °C and the results showed that the preference of four tested fungal cellulases to the substrates with different polymorphs followed the order of cellulose I, I/II to II. However, when the experiments conducted at 45 °C, the exhibited hydrolytic activity of substrates followed an inverse order. As such, it can be concluded that in the whole process of enzymatic hydrolysis, treatments involving polymorphic conversion from cellulose I to II reduces the speed of CBM recognition but facilitates the hydrolysis reaction, and therefore the overall performance of polymorphic conversion is beneficial to enzymatic hydrolysis.