Biocatalysis is an emerging and transformational technology uniquely suited to the manufacture of active ingredients in the pharmaceutical and related industries. Traditionally, biotransformations of organic compounds were catalyzed by whole cells and the applications to chemical syntheses were significantly limited due to low substrate loading capability and modest yields. As rapid DNA sequencing technology and efficient protein expression systems emerged, the discovery, cloning and production of individual enzymes has become much more straightforward and efficient. Practical biotransformations can now be accomplished using isolated enzymes, leading to higher substrate loading and greater yields.