Alpha-L-Rhamnosidase from Aspergillus terreus Immobilized on Ferromagnetic Supports

F. SORIA; G. ELLENRIEDER; L. BEZERRA DE CARVALHO JR.

San Pablo - Brasil

Workshop; III Workshop de Biocatálise - II Encuentro Regional de Biocatálisis y Biotransformaciones; 2006

Universidad de San Pablo - Brasil

Aspergillus terreus CECT 2663 a-L-Rhamnosidase was covalently immobilized on the ferromagnetic supports hydrazide dacron, polisiloxane/polyvinyl alcohol (POS/PVA) and chitosan. The powdered supports were magnetized by reaction with ferreous (Fe2+) and ferric (Fe3+) ions at pH 10 and the immobilization was carried out on the glutaraldehyde activated materials. Optimum pH, temperature of maximum activity kinetics constants and thermostability were determined and compared with those  of the  free enzyme. The activity of the Dacron and POS/PVA immobilized enzyme was appreciably higher than that of previously reported values for a-L-Rhamnosidase. The thermal stability at 60°C of the POS/PVA and Chitosan preparations was somewhat higher than that of the free enzyme. The activity of the preparations did not decrease appreciably after ten successive  uses.