A simple method was presented for obtaining good approximate solutions of diffusionreaction boundary value problems in immobilized enzyme.Based on approximate solutions for diffusionreaction problems,the mathematical expressions for calculating effectiveness factor of immobilized enzyme were proposed.Calculations of effectiveness factor were made with MichaelisMenten kinetic expression for spherical immobilized enzyme pellet.The results show that the agreement of approximate solution of effectiveness factor with numerical solution obtained by numerical method is satisfactory in a wider parameter range.The presented method for calculatin effectiveness factor of immobilized enzyme is simple and the calculation is fast.
