Hydrolysis of sucrose by invertase as a typical example of saccharides enzymatic hydrolysis has been conducted in a UF-stirred cell reactor. A model has been derived by which the effect of some pertinent variables, such as membrane pore size, applied pressure. substrate concentration and stirring speed, on the performance capability of such systems may be predicted. A close correlation has been found between the experimental results obtained under a wide range of operating conditions and those calculated from the model.