The enzymatic synthesis of n-octyl oleate by direct esterification of the oleic acid and the octanol in a solvent-free medium was previously shown to be efficiently catalysed by a lipase from Rhizomucor miehei covalently linked to a graft copolymer, the partially hydrolysed poly(ethylene)-g co-hydroxyethyl methacrylate (PE-g co-HEMA). In this work we went further towards an optimisation of the production of n-octyl oleate taking into account several parameters that affect the catalytic activity of the preparation. The physical characteristics of the support, such as the particle size and the degree of hydrolysis of the copolymer, the amount of lipase used in the method of immobilisation, the water content of the reaction mixture and the operational conditions of reaction, in particular the temperature, were evaluated in order to achieve not only high activities but also a good stability of the preparation.