CHAPTER 12: Process Intensification of Enzymatic Biotransformation Processes

This chapter provides a short review of the field of enzymatic biotransformation and its application to chemical reactions and products of industrial relevance. Specifically, the important role of process intensification in the application of biotransformation technology is reviewed. Biotransformation covers a wide range of chemical and biochemical processes, including biocatalysis, fermentation processes, and biologically based waste treatment processes. We focus, here, mostly on biocatalytic reactions, processes, and related separations. The relevance of enzymatic biotransformation to green chemistry is also analyzed and discussed. Since many enzymatically catalyzed reactions are slow and have challenging separation requirements, the nexus between enzymatic biotransformation and process intensification technology is particularly important. Here, we summarize process intensification as an equipment technology, catalyst, reagent, solvent, or chemical pathway which enables product synthesis at a higher rate, in a smaller volume, generating less waste, and consuming less energy than the conventional alternative. Examples of process intensification research which we have successfully applied to enzymatic biotransformations are described. These include extractive whole cell biotransformation involving the benzylic chiral hydroxylation of naphthalene in the presence of an ionic liquid solvent. A second example is the lipolytic hydrolysis of a triglyceride ester using a microbial lipase. Performance of microbial lipase on different polymeric supports is briefly considered, showing the reduction in reaction kinetics when the enzyme is immobilized compared with deployment in free solution. Finally, the intensification of the lipolytic hydrolysis of a triglyceride ester in the presence of an electrical field using enzyme in free solution is described. A summary is presented of the mathematical modeling capability which has been demonstrated for evaluation of reactor design options.