Theoretical and experimental studies on the influence of ultrasound on immobilized enzymes

Experimental investigations on alpha-amylase and glucoamylase bound to porous polystyrene show that the activity of immobilized enzymes can be raised in the presence of an ultrasonic field. The maximum activity increase in a flow cuvette at 7.6 MHz and a sound intensity of 5 kW/m(2) amounts to more than 200% under the given experimental conditions. A mathematical model based on the differential equation for the interior and exterior substrate transport is set up and solved numerically. From the theoretical considerations and the experiments it is evident that the mechanism of the ultrasonic effect can be explained in terms of a reduction of the unstirred diffusion layer around the matrix particles.