A system is proposed for the continuous synthesis of an acyl erythritol through the immobilised-lipase-catalysed condensation of the corresponding fatty acid and erythritol in acetone. A fatty acid dissolved in acetone was fed to a column packed with erythritol powders, and erythritol was dissolved in the column at a saturated concentration. The effluent from the column was introduced to a packed-bed reactor of immobilised lipase from Candida antarctica to produce the acyl erythritol. Some saturated acyl erythritols and oleoryl erithritol could be continuously synthesised using this system. A selectivity higher than 0.8 was obtained for the monolauroyl erythritol synthesis at 50 mmol/l of lauric acid, with residence times longer than 4.5 min and 60 degreesC. The system could be stably operated at 60 degreesC for at least 2 weeks without any loss of enzyme activity. Productivities of 1.25 and 1.36 kg/l-reactor day were achieved for the synthesis of the lauroyl and oleoyl erythritols, respectively. (C) 2003 Elsevier Ltd. All rights reserved.