Ultrasonic assisted enzymatic reaction: An overview on ultrasonic mechanism and stability-activity of the enzyme

The aim of this study is to review on mechanism of ultrasonic irradiation in enzymatic esterification reaction, the effect on enzyme activity and stability and also rate of reaction in ultrasonic assisted enzymatic reaction. Conventional enzymatic esterification system using immobilized enzyme generally have a limitation in internal mass transfer that might plausible to reduce rate of ester formation. However, this obstacle can be overcome using ultrasonic system that offers different movement of the molecule. The mechanism of ultrasonic is based on the high energy waves that create cavitations in the liquid solution. Better cavitations are attained at high amplitudes, nucleation sites, lower temperature, external pressure and dissolved gas. While for the activity and stability of the enzyme during ultrasonic irradiation process, appropriate wave duty cycles, acoustic power, prolong of exposure and support materials are required in order to retain the stability and activity of the enzyme. Application of ultrasonic irradiation in enzymatic esterification reaction enhanced mass transfer and diffusion of substrate and product within the reaction medium. This factor results in higher reaction rate as compared to the mechanical agitation.