This work presents a detailed mathematical model and design methodology for a simulated moving bed reactor (SMBR) intended to invert sucrose by enzymatic action and simultaneously separate the products glucose and fructose. Experimental results for the operation of a SMBR are shown and very good agreement with simulated results was obtained. The design/optimisation package is based on an algorithm, previously developed for non-reactive SMB, used to define both the geometric parameters (column length and diameter), enzyme concentration and operating conditions of a simulated moving bed reactor. In this strategy, a detailed model is used instead of a simple equilibrium stage model. The objective of the strategy is to calculate minimum column lengths and enzyme concentrations for given feed flowrates, constrained by a reaction conversion not <99% and purities not <95% for both extract and raffinate products. Optimisation is achieved by defining the enzyme productivity as the objective function to be maximised. Design algorithm results are shown for different values of fluid/solid velocity ratios on Sections 1 and 4. This way, the effects of the safety margin applied to gamma (1) and gamma (4) have been investigated on the reaction conversion and separation performance. The results have been compared with predictions from the equilibrium theory for a non-reactive system and the observed deviations have been evidenced and discussed.