Introduction

Biotransformation deals with the use of biological catalysts to convert a substrate into a product in a limited number of enzymatic steps. The establishment of an efficient biotransformation process requires the extensive examination of factors affecting the development of optimal biocatalysts, reaction media and bioreactors (Fig. 24.1).

The chemical industry currently takes advantage of enzyme technology in various sectors, namely in the food, pharmaceutical and detergents sectors. An on-going trend towards the implementation of commercial processes based on the use of biocatalysts in other areas (e.g. polymers, fine and agricultural chemicals, and miscellaneous chemicals) is noticeable. It is foreseeable that in the near future the use of biocatalysts in these fields will be enhanced which, coupled to the already established bioprocesses, will further broaden the overall impact of biocatalysis in the chemical industry. When compared to equivalent chemical processes, bioprocesses are simpler, less demanding in raw materials and in energy, lead to higher quality products (i.e. with fewer impurities) and produce higher yields, lower the involvement of toxic wastes and decrease the emission of wastewater. Such features decrease production costs and, since bioprocesses easily comply with the stringent environmental legislation in highly regulated countries, these processes are given a competitive edge when matched up to conventional (chemical) methods. In many cases, near-term benefits will increase as the market penetration of the product and process continues to grow, leading to further cost reduction and performance improvements relative to competing products and processes.