beta-Glucosidase from almonds (EC 3.2.1.21) was covalently immobilized by a two-step technique. In the first step, double bonds were introduced into the beta-glucosidase by derivatization with itaconic anhydride. In separate studies with alpha-N-protected L-amino acids, it was established that itaconic anhydride acylated mainly primary amino groups of lysines and, to a much lesser extent hydroxyl groups of tyrosines and sulfhydryl groups of cysteines. The acylated beta-glucosidase showed no loss of activity and the K-m decreased from 3.6 mM to 2.6 mM when p-nitrophenyl beta-D-glucopyranoside was used as the substrate. In the second step, the derivatized beta-glucosidase was co-polymerized radically with N,N＇methylenebisacrylamide in buffer solution. The resulting acrylamide immobilizate possessed a much better storage stability at 30-56 degrees C when compared to beta-glucosidase immobilized on Eupergit C. However, the specific activity was higher with the Eupergit immobilizate. Free and acrylamide-immobilized beta-glucosidase were used for glucosylation of chloramphenicol by transglucosylation in 20% (v/v) acetonitrile at 37 degrees C. The acrylamide immobilizate demonstrated a great enhancement of stability and approximately 50% more chloramphenicol beta-glucoside was obtained after 5 h.