A review of applications of cavitation in biochemical engineering/biotechnology

Cavitation results in the generation of hot spots, highly reactive free radicals, and turbulence associated with liquid circulation currents, which can result in the intensification of various physical/chemical operations. The present work provides an overview of the applications of the cavitation phenomenon in the specific area of biochemical engineering/biotechnology, discussing the areas of application, the role of cavitation, the observed enhancement and its causes by highlighting some typical examples. The different methods of inducing cavitation and the dominance of one over the other, mostly with respect to energy requirements, in different areas of biotechnological application are discussed. The major applications discussed in the work include microbial cell disruption for the release or extraction of enzymes, microbial disinfection, wastewater treatment, crystallization, synthesis of biodiesel, emulsification, extraction of bio-components, freezing and gene transfer into cells or tissues. Some recommendations for optimal operating/geometric parameters have also been made. Overall, it appears that the combined efforts of physicists, chemists, biologists and chemical engineers are required to effectively use cavitational reactors for industrial applications. (C) 2008 Elsevier B.V. All rights reserved