Candida antarctica lipase B-catalysed synthesis of dihydroxyacetone fatty acid esters

The enzymatic syntheses of 1-lauroyl-dihydroxyacetone and 1,3-dilauroyl-dih ydroxyacetone were investigated. Lipase B from Candida antarctica (SP435) w as used to catalyse the acylation of dihydroxyacetone (DHA) with lauric aci d in organic solvent media at controlled water activity. High conversions o f dihydroxyacetone (> 90%) are achieved when the water activity is 0.11 or below in solvents of various hydrophobicities, such as diethyl ether, methy l-tert-butyl ether (MTBE) and diphenyl ether. The main product in the ester ification of DHA with lauric acid is 1-lauroyl-DHA, while the amount of 1,3 -dilauroyl-DHA that is produced can be increased by changing the reaction c onditions. Thus, decreasing the water activity from 0.75 to 0.06 resulted i n an increase in the total yield of 1,3-dilauroyl-DHA from 3% to 20%. Solve nts which have high log P values favoured the acylation of 1-lauroyl-DHA an d thereby the formation of 1,3-dilauroyl-DHA. Thus, when diphenyl ether was used in this reaction, the yield of 1,3-dilauroyl-DHA was 45%. Complete ac ylation to 1,3-dilauroyl-DHA was achieved when a fatty acid vinyl ester was used as acyl donor in a dosed reactor.