Abstract Catalase is a potentially useful biocatalyst in various industrial bioprocesses (textile industry, food processing, and pulp and paper) that require removal of hydrogen peroxide. This process can be achieved in such reactors even under isothermal conditions. However, it is usually connected with a long duration of the process or with spending a considerable amount of biocatalyst for a unit mass of the transformed substrate, which in turn leads to an increase in operating costs. They can be limited by applying the optimal temperature control, which requires the values of the thermodynamic parameters -the activation energy for reaction and the activation energy for deactivation must be known. This work reports these parameters for hydrogen peroxide decomposition and Aspergillus niger catalase deactivation at temperatures ranging from 35ºC to 50ºC.