A Novel Approach: Lipase Catalyzed Esterification of 
2-monoacylglycerol and Nα-acetyl-L-leucine
Hasene Keskin*, Derya Koçak Yanık, Fahrettin Göğüş, Sibel Fadıloğlu
The University of Gaziantep, Engineering Faculty, Food Engineering Department, 27310 Gaziantep, TURKEY.
*hasenekeskin@gantep.edu.tr

The enzymatic esterification reaction of 2-monoacylglycerol and Nα-acetyl-L-leucine was performed using immobilized lipase from Candida antartica, Mucor miehei and Thermomyces lanuginosus. The reaction involved the lipase-catalysed esterification of one or two hydroxy groups of the 2-monoacylglycerol by Nα-acetyl-L-leucine. Lipase from Thermomyces lanuginosus was found to be the most effective enzyme amongst the studied lipases. This enzymatic esterification reaction is limited by the fact that most of the lipases are inactivated by the polar solvents in which amino acids are soluble. Different organic solvents and their mixtures were studied to overcome this limitation. A lipase-catalyzed process using a medium constituted by two miscible solvents was developed. Hexane:DMF (95:5, v:v) was particularly effective organic solvent mixture for this esterification reaction. 1,3-di(Nα-Ac-L-leucine)-2-O-acyl-rac-glycerol and 1(3)-Nα-Ac-L-leucine-2-O-acyl-rac-glycerol were detected in the final reaction mixture as 11.81 and 10.30%, respectively. 

Acknowledgments: This study was supported by TUBITAK (Project code; MAG 113M471)                                                                                                                  Keywords: 2-monoacylglycerol, enzymatic esterification, Nα-acetyl-L-leucine, organic solvent