Chemical transesterification is of major importance to the edible oil industry. While alkali catalysts randomize all the fatty acids in a triglyceride mixture, the use of a 1,3 specific lipase causes a more selective exchange of fatty acid residues. Basic process parameters for the development of a continuous solvent-free process in a fixed bed reactor have been determined. The kinetics of the transesterification reaction and the influence of particle diameter, substrate and water concentration on the effective reaction rate were examined in batchwise experiments. Residence time distribution and parameters of inter-and intraparticle mass transfer were determined by modelling of experiments carried out in a fixed bed reactor under transient conditions. Fixed bed reactors with side stream analysis were used for continuous transesterification. A kinetic model was developed for the enzyme catalyzed reaction, thereby showing the analogy between heterogeneous catalytic and enzyme catalyzed reactions. A one-dimensional heterogeneous reactor model was formulated on the basis of the kinetic equation and different process parameters. For numerical calculations, an exponential enzyme distribution inside the carrier was assumed. The simulation of experimental results indicates that they are well described by the developed model. Water concentration and presence of other substances strongly influence the stability of the immobilized enzyme.