Fatty acid sugar esters are non-ionic surfactants which are widely used in food, cosmetic and pharmaceutical industry. Lipase-catalyzed synthesis of fructose with fatty acid in organic medium was performed in a batch reactor at atmospheric pressure. Influence of different reaction parameters, such as different kinds of lipase preparations and organic solvents, biocatalyst concentration, molecular sieve concentration, temperature, stirring rate and the use of different fatty acids as acyl donors was studied. Optimum conditions were found using 10% (w/w of substrates) lipase from Candida antaretica B (Novozym 435) and 12.1% (w/w) of molecular sieves at 60 degrees C and stirring rate of 600 rpm. The highest conversion was obtained in ethyl methylketon (82%), which is permitted for general use in the manufacture of food additives. (c) 2005 Elsevier Ltd. All rights reserved.