A novel sugar ester using 9-cis,11-trans isomer of conjugated linoleic acid (CLA) was produced as a bioactive surfactant. In the first part of study, conjugated linoleic acid (mixture of all isomers but particularly 9-cis,11-trans one) was produced from castor oil and process optimization was done using response surface methodology (RSM). The temperature, 50 ? C; catalyst amount, 1.8 g and reaction time, 5.25 h were found to be the optimum points to achieve the maximum yield of 9c,11t -18:2 (54.4%). In the second part, 9c, 11t -18:2 isomer was separated from other isomers in an organic solvent-free system using lipase extracted from Candida rugosa and the effects of synthesis parameters were evaluated and optimized. The optimum synthesis conditions were obtained to be as reaction time 23.12 h, temperature 32.65°C, enzyme amount 135.40U, molar ratio of CLA oil to L-menthol at 1:1.7 and pH at 7.7; the highest purity of 9c, 11t -CLA in this optimum point was 82.5%. At the final part, after determination of suitable solvent, sugar and enzyme, experimental operating conditions were optimized to maximize production of fructose monoester. The temperature 49.1 ° C, 123.7 mg of lipase TL IM, CLA to fructose ratio 1:1.68, 13.57 mg molecular sieve and 30.32 h were found to be the optimum points to achieve the maximum yield of sugar monoester (6.5 mg/ml). After purification and determination of several active/functional properties of the monoester, it was found that this compound had suitable and acceptable properties that can further be studied as a bioactive surfactant for application in different food products. Key Words Non-ionic surfactants, Sugar monoester, Castor oil, Candida rugosa , Optimization
