Some factors influencing easy immobilization procedures on Nylon and chitin supports were optimized in terms of the highest activity of immobilized pectinlyase, using two experimental designs. Optimal procedures were applied to co-immobilized pectinlyase (P1, EC 4.2.2.3) and endocellulase (Cx, EC 3.2.1.4), using a commercial enzyme but omitting preliminary purification steps. Purified enzyme solutions were not used. The kinetic characteristics of co-immobilized pectinlyase and endocellulase were assessed for both supports. Chitin was more suitable for applications to fruit juice liquefaction because both immobilized pectinlyase and endocellulase showed higher activity at low pH and low temperature. Furthermore. the half-life of pectinlyase bound to chitin was higher than with Nylon (407 h against 19 h). The immobilization procedure on chitin was not only inexpensive, but also very easy to carry out so that the potential for industrial application is considerable. (C) 2000 Elsevier Science Ltd. All rights reserved.