*2.5.2.2. Esterification*

Esterification is the reverse reaction of hydrolysis and is used to synthesize selected products under appropriate reaction conditions [70]. The products of an esterification reaction are usually an ester and water. The water content of esterification reaction system strongly effects on lipase activity. Low water content shifts the equilibrium of the reaction to favor the synthesis of lipids. So that additional techniques were used to drive synthesis reaction including removal of water that formed during the process by evaporation under reduced pressure [71] or by adding molecular sieves to adsorb the water. Direct enzymatic esterification of some primary alcohols and selected carboxylic acids was catalyzed by the *Candida antarctica* and *Rhizomucor miehei* lipases. The reactions were performed in solvent-free medium with the removal of water [72].
