Chapter 14: Fermentations and Sustainable Technologies: From Free Enzymes to Whole Cells, from Fine Chemicals to Bulk Commodities

The so-called white biotechnology (i.e. the use of enzymes, resting cells and growing organisms as biocatalysts) has emerged in past decades as a powerful alternative to perform environmentally friendly syntheses with high selectivity and efficiency. This chapter provides an introductory overview of the important aspects related to the use of different biocatalysts in organic synthesis, ranging from key aspects of molecular biology such as gene cloning and overexpression in heterologous hosts, together with their genetic improvements of desired enzymes, to the different parameters that need to be assessed for a successful industrial biotransformation. Included in the chapter are interesting examples of using free enzymes, resting (non-growing) whole cells and fermentations (living cells), emphasizing in each case which are the important aspects for process development. Rather than being a comprehensive review of industrial biocatalytic processes, the selected examples are used to showcase how industrial biotransformations are built for real applications.