Study of an enzyme membrane reactor with immobilized fumarase for production of L-malic acid

The conversion of fumaric acid into L-malic acid by fumarase immobilized in a membrane reactor was analyzed experimentally. The enzyme was entrapped i n asymmetric capillary membranes made of polysulfone. The performance of th e reactor was evaluated in terms of conversion degree, reaction rate, and s tability. The influence of operating conditions, such as amount of immobili zed enzyme, substrate concentration, residence time, and axial flow rate, w ere investigated. The kinetic parameters K-m, V-max, and k(+2) were also me asured. The stability of the immobilized enzyme was very good, showing no a ctivity decay during more than 2 weeks of continuous operation. (C) 2001 Jo hn Wiley & Sons, Inc.