Enzymatic Syntheses of Esters - Green Chemistry for Valuable Food, Fuel and Fine Chemicals

The esterification is well-established type of reaction in organic synthesis used for manufacturing various valuable esters used prevalently as ingredients of food, skincare products, pharmaceuticals and fuels. In recent decades biocatalytic synthetic routes based on using enzymes as catalysts have received a lot of attention in scientific researches and industry. Main advantages of enzymatic esterifications are high selectivity (regioselectivity and enantioselectivity), performing reaction at milder conditions (moderate temperature and atmospheric pressure) and the fact that enzymatically synthesized product gain label of natural product, which increases its market appeal. The purpose of this review is to point out the most important advances in lipase-catalyzed ester synthesis in nonconventional reaction media, with special focus on several most important types of ester. This part of review starts with outcomes in synthesis of aroma esters, usually obtained using monofunctional aliphatic alcohols and acids, which have been investigated for decades and industrial processes are already established. However, later sections are dedicated to enzymatic esterification of more complex molecules (carbohydrates, vitamin C, flavonoids) having more than one functional groups, which are subject of numerous studies in recent times because in these reactions regioselectivity of biocatalysts can be fully explored and processes are still subject of optimization, especially with respect to selection of reaction media and media engineering.