Application of potato lipid acyl hydrolase for the synthesis of monoacylglycerols

Protein extracts from potato tubers contain a lipid acyl hydrolase (LAH) with an unusual selectivity. The component responsible for the enzyme activity is a group of closely related glycoproteins, known as patatin. Potato LAH catalyzes the rapid hydrolysis of monoacylglycerols (MAC), but in contrast expresses only low activity with di- and triacylglycerols. The selectivity of the LAH can be exploited for the synthesis of MAG from fatty acids and glycerol in microaqueous reaction systems. Oleic, linoleic, linolenic, capric, lauric, and myristic acids can be used as reactants, and in each case the reaction products contain >95 mol% MAG and <5 mol% diacylglycerol. By removing water from the reaction mixture by distillation under vacuum, excellent conversions of fatty acids into MAC are possible. Low conversions are observed with palmitic and stearic acids, because of the necessity to use a high temperature (70 degrees C) to maintain a liquid reaction mixture. Potato LAH is rapidly inactivated at 70 degrees C in the microaqueous reaction systems. Potato LAH also catalyzes the selective synthesis of monoesters from oleic acid and simple diols. With oleic acid and diglycerol, monoesters are again the main reaction products, but 17 mol% diesters are also formed.