The synthesis of wax ester using refined, bleached and deodorized (RBD) palm oil and oleyl alcohol catalyzed by lipozyme IM was carried out. Response surface methodology (RSM) based on a five-level, four-variable central composite rotatable design (CCRD) was used to evaluate the interactive effects of synthesis, of reaction time (2.5-10 h), temperature (30-70 degrees C), amount of enzyme (0.1-0.2 g) and substrate molar ratio (palm oil to oleyl alcohol, 1: 1-1:5) on the percentage yield of wax esters. The optimum conditions derived via RSM were: reaction time 7.38h, temperature 53.9 degrees C, amount of enzyme 0.149g, and substrate molar ratio 1:3.41. The actual experimental yield was 84.6% under optimum condition, which compared well to the maximum predicted value of 85.4%. (c) 2005 Elsevier Inc. All rights reserved.