The hydrolysis of lactose using the enzyme lactase from Aspergillus oryzae and the simultaneous separation of the products galactose and glucose was examined in a Simulated Counter-Current Chromatographic Bioreactor-Separator (SCCR-S) system. The system was operated in continuous and batch modes and the results obtained used to compare the performance in both modes. Mathematical modelling and computer simulation of the system operating in the continuous mode are reported.