Numerical and experimental study of microorganism disruption using shock treatment

Abstract

The use of shock waves to destroy microorganisms is considered one of the newly developed methods in the field of cell disruption. This simulation part of this research work aims to determine the required shock pressure to disrupt a single yeast cell and the rupture location on the cell wall. As a step towards understanding the physical response of the microorganisms to dynamic pressure and shock treatments a Finite Element (FE) model has been developed using commercial software ABAQUS. Von Mises theory of failure is adopted in this work and the properties of Saccharomyces cerevisiae (S. cerevisiae) reported in the literature were used in the numerical and experimental work. The simulation results demonstrate that maximum dynamic σv/Pe (0.85) was found to be over three times that of the static σv/Pe (0.25) values. This suggests a location of the rupture within the cell wall when shock pressure loading is applied; such a result has not been previously reported in current literatures. In the experimental work, a gas gun tunnel was used to generate 100–400 MPa external pressure loading on a yeast suspension. The experimental results showed that the maximum yeast reduction of 95.7% resulted when a 336 Mpa pressure rise was applied.