Enzymatic synthesis of unsaturated fatty acid glucoside esters for dermo-cosmetic applications

Unsaturated fatty acid alpha-butylglucoside esters were prepared by enzymat ic esterification of alpha-butylglucoside in nonaqueous media. Conditions w ere firstly optimized using oleic acid as acyl group. Synthesis was possibl e in several solvents but the presence of water co-product in the medium li mited the reaction to a thermodynamic equilibrium corresponding to a maxima l conversion yield of 62%. In pure molten substrates, the removal of water under reduced pressure enabled yields superior to 95% to be obtained. Produ ct profiles depended on enzyme origin : whatever the support, immobilized l ipase B from Candida antarctica proved to be far more regioselective for th e primary hydroxyl group of glucose than immobilized lipase from Rhizomucor miehei. Results obtained could be easily transposed to the acylation of al pha-butylglucoside with a commercial mixture of unsaturated fatty acids con taining more than 60% of linoleic acid. The biocatalyst could be recycled m ore than ten times without any significant activity loss. (C) 1999 John Wil ey & Sons, Inc.