The catalytic activity of lipases toward hydroxy fatty acids - A review

Hydroxy fatty acids, derived from several natural and synthetic sources, have many applications. Lipases have been employed to catalyze reactions involving hydroxy acids to narrowly shape the product distribution via their regio- and stereoselectivities. This manuscript reviews the action of lipase on hydroxy acids and their derivatives. The formation of estolides or lactones by lipase-catalyzed reactions depends strongly on the position of the hydroxyl moiety on the hydroxy acyl group and slightly on the hydroxy acid chainlength and concentration. Pseudomonas sp. and porcine pancreatic lipases are the most useful for catalyzing formation of optically pure lactones, while lipases lacking positional selectivity catalyze estolide formation best. The product distribution of lipase-catalyzed esterification between hydroxy- and nonhydroxy-acyl groups is strongly dependent on the lipase type. Lipase-catalyzed reactions between hydroxy acids and alcohols yield hydroxy esters, not estolides, as the major product.