ABSTRACT
Biotechnology is being increasingly adopted by several chemical companies to improve manufacturing sustainability and profitability as regards energy consumption and feed stock access as well as the production o f high-value chemicals.1,2 Industrial biotranformations generally center around natural compounds such as carbohydrates and fats in food sector (Fig. I).3 However, the pharmaceuticals sector has started dominance in this area (Fig. 2).4 Chemical and pharmaceutical industries need eco-friendly and benign technologies and thus waste minimization o f both material and energy and catalysis are at the hub o f all green processes. A practical alternative to the traditional organic synthesis is biotechnology and in particular enzymatic catalysis is weighed against chemical catalysis in fine chemical and pharmaceutical industries. Enzymes are exquisitely selective in catalyzing reactions with unparalleled chiral and regio selectivities. Enzymes typically operate at room temperature and ambient pressure and lead to a few waste products; neither do they need the tedious blocking and deblocking steps that are common in enantio and regio selective organic synthesis. Chirality is o f utmost impor tance in drug synthesis. Chiral nature o f the enzymes is responsible for their chemo, regio-and stereospecificity. A typical enzyme with a mass o f 50,000 daltons possesses 4 5 0 amino acid residues: 19 chiral L-aminoacids and glycine and further i f glycine makes up 10% o f the residues, then there are at least 400 residues with chiral centers to provide an asymmetric environment for substrate binding and subsequent chemical transformation. There is a requirement to develop processes fo r the production o f enantiom erically pure drugs. The market fo r single isomers o f chiral drugs is more than 100 billion US dollars and continue to expand rapidly.5
