Although numerous reactions have been performed using lipases and related enzymes (e.g. esterases and phospholipases), it is still a challenge to identify the most suitable biocatalyst and best reaction conditions for an efficient application. Frequently used methods such as immobilization and optimization of the reaction medium cannot be transferred from one reaction system or substrate to another. However, in the past few years, rational protein design and directed evolution have emerged as efficient alternative methods to optimize biocatalytic reactions.