The Inactivation of Enzymes by Ultrasound-A Review of Potential Mechanisms

The application of ultrasonic energy can inactivate many enzymes. The ultrasound shock waves produce cavitation and acoustic streaming in the liquid medium, which generates adequate mechanical, thermal, and chemical effects to inactivate enzymes. The extremely fast cycles of pressurization and depressurization and the resultant (localized) high temperature lead to rapid formation and collapse of bubbles. The rapid formation and collapse of bubbles is capable of breaking the hydrogen bonds as well as the van der Waals interactions in polypeptide chains. The application of ultrasound alters the secondary and tertiary structure of enzymes and leads to the loss in their biological activity. In this article, the authors review the recent advances made in the inactivation of common enzymes by the application of ultrasound alone or in combination with heat and pressure. The associated inactivation mechanisms and the factors affecting the enzyme inactivation are also reviewed.