Cell Disruption

Abstract

To exploit the range of bioproducts from microbial sources, liberation of intracellular products is essential where not secreted into the suspending media by the microbial construct. The cell wall provides structural strength and typically the key resistance to product liberation. The cell membrane is readily disrupted in its absence. Accordingly, a discussion of cell-wall structure of key microbial systems is presented. A comprehensive discussion of the following cell disruption approaches is given: mechanical disruption in high-pressure systems and bead mills, hydrodynamic cavitation, ultrasonic cavitation, chemical, enzymic, osmotic, and thermal treatments. It is recognized that mechanical cell disruption by high-pressure homogenization (HPH), high-speed bead mills, and associated approaches is most commonly used on a large scale. Focus on HPH as a key example is used to discuss mechanism and modeling of the sample disruption process. New approaches with potential for scaleup are highlighted. Integration of cell disruption with the product formation and product recovery and purification phases is important. Selective product release is sought to minimize contaminating load. Pretreatment may reduce energy requirement, avoid micronization of cell debris, and influence cell deactivation. Characteristics of the cell lysate, for example, its contaminating load, particle size, and viscosity, and their influence on the subsequent downstream process are discussed.