In this study, the effects of various buffers and ionic strengths on the immobilization of Candida rugosa and Rhizopus oryzae lipases were investigated to enhance the activities of the immobilized lipases Among. the various buffers, the optimal buffers and ionic strength for the immobilization of C rugosa and R. oryzae lipases were determined to be a mixture of 0.25 M MOPs and sodium phosphate buffer (pH 6.5). Moreover, the activities of immobilized C. rugosa and R. oryzae lipases under their optimal conditions were 3756.11 and 2845.21 U/g matrix, respectively. Furthermore, the activity of immobilized lipases increased by approximately 4.13 and 3.1 times after 24 h, respectively. Finally, the activities of the immobilized lipases were maintained at levels greater than 90% of their original activities after ten reuses and at levels greater than 60% of their original activities after twenty reuses. (C) 2009 Elsevier Ltd. All rights reserved.