Chitinase Activity on Amorphous Chitin Thin Films: A Quartz Crystal Microbalance with Dissipation Monitoring and Atomic Force Microscopy Study

Abstract

Chitinases are widely distributed in nature and have wide-ranging pharmaceutical and biotechnological applications. This work highlights a real-time and label-free method to assay Chitinase activity via a quartz crystal microbalance with dissipation monitoring (QCM-D) and atomic force microscopy (AFM). The chitin substrate was prepared by spincoating a trimethylsilyl chitin solution onto a silica substrate, followed by regeneration to amorphous chitin (RChi). The QCM-D and AFM results clearly showed that the hydrolysis rate of RChi films increased as Chitinase (from <i>Streptomyces griseus</i>) concentrations increased, and the optimal temperature and pH for Chitinase activity were around 37 °C and 6–8, respectively. The Chitinase showed greater activity on chitin substrates, having a high degree of acetylation, than on chitosan substrates, having a low degree of acetylation