Selective lipase-catalyzed synthesis of glucose fatty acid esters in two-phase systems consisting of an ionic liquid (1-butyl-3-methyl imidazolium tetrafluoroborate [BMIM][BF4] or 1-butyl-3-methyl imidazolium hexafluorophosphate [BMIM][PF6]) and t-butanol as organic solvent was investigated. The best enzyme was commercially available lipase B from Candida antarctica (CAL-B), but also lipase from Thermomyces lanuginosa (TLL) gave good conversion. After thorough optimization of several reaction conditions (chain-length and type of acyl donor, temperature, reaction time, percentage of co-solvent) conversions up to 60% could be achieved using fatty acid vinyl ester as acyl donors in [BMIM] [PF6] in the presence of 40% t-BuOH with CAL-B at 60 degrees C. (c) 2005 Elsevier B.V. All rights reserved.