Comparative studies on the sugar esters synthesis catalysed by Candida antarctica and Candida rugosa lipases in hexane

The regioselective acylation of monosaccharides, such as glucose, fructose, mannose and arabinose with lauric acid (C12) has been investigated in hexane using commercial Candida rugosa lipase (EC 3.1.1.3) and Candida antarctica (NOVOZYME) lipase immobilised on anionic resin. In order to overcome sugars insolubility in hexane, sugars were introduced in the reaction mixture preabsorbed on silica gel. The chemical structure of the products has been determined by H-1 NMR analysis. The two enzymes tested seemed to prefer hexoses rather than pentoses as the sugar substrate. They exhibited different water activity optimums as well as different optimum sugar/acyl donor molar ratios. Water activity control throughout the reaction and temperature increase from 30 to 50 degrees C enhanced sugar ester production using both lipases.