Measurement of Cellulase Activity with Piezoelectric Resonators

We examined the dynamics of cellulase binding and activity on thin films of cellulose by using a piezoelectric sensing device (Quartz Crystal Microbalance with Dissipation monitoring, QCM-D). Upon exposure of the cellulose film to enzyme mixtures, a reduction in the sensor’s frequency due to molecular binding is observed. Thereafter the frequency increases due to the loss of effective mass caused by the degradation of the film (enzymatic attack). We demonstrate that the rate at which degradation of the film occurs can be monitored and quantified in situ and in real time as a function of enzyme concentration, temperature and pH of the incubating solution. Also, mass transport effects can be investigated by changing the flow conditions within the QCMD reaction cell. The use of piezoelectric sensing to characterize and monitor the mechanisms and kinetics of enzyme activity on cellulosic substrates adds another dimension to our knowledge and to the methods available for such investigations.