Long-chain fatty acid esters are useful functional molecules responding to the requirements of numerous fields of application in cosmetic, pharmaceutical and lubricant industry. In the present work, lipase-catalysed production of n-octyl oleate by esterification of oleic acid with I-octanol in dense CO2, as reaction medium, was performed in bench-scale packed-bed bioreactor, in order to obtain suitable reaction performance data for up-scaling. Lipase from Rhizomucor miehei (Lipozyme RM IM) was used as the biocatalyst. The experiments were planned to elucidate the effect of several process parameters, such as pressure, temperature, CO2 and substrates flow rates. Pressure of 10 MPa, temperature of 323.15 K, CO2 flow rate of 210 dm(3)/h and substrates flow rate of 18 cm(3)/h were predicted to be the optimum conditions: a maximum yield of about 93% was attained. Performing the enzymatic reaction in the continuously operating bioreactor, a long-term enzyme lifetime was observed and a decrease of the Lipozyme activity was not registered over 50 days. A comparison with experimental results obtained in batch-wise was also proposed. Operating at the optimum reaction conditions, higher ester yield than those obtained in batch-mode was detected. Supercritical carbon dioxide (SC-CO2) showed to be a potential medium for the n-octyl oleate biosynthesis for a large-scale production in continuous-mode. (c) 2006 Published by Elsevier B.V.