Simplified optimization method using the MATLAB function fminbnd was adopted to determine the optimal feed temperature (OFT) for an isothermal packed-bed reactor (PBR) performing hydrogen peroxide decomposition (HPD) by immobilized Terminox Ultra catalase (TUC). The feed temperature was determined to maximize (minimize) the average reactant conversion (reactant concentration) over a fixed period time at the reactor outlet. The optimization was based on material balance and rate equation for enzyme action and decay and considered the effect of mass-transfer limitations on the system behavior. In order to highlight the relevance and applicability of the work reported here, the case of optimality under isothermal operating conditions is considered and the practical example is worked out. Optimisation method under consideration shows that inappropriate selection of the feed temperature may lead to a decrease in the bioreactor productivity.