Immobilization of alpha-L-Rhamnosidase from Aspergillus terreus on a Polyaniline Silicone Tubing Composite

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

Brasil. Caxias do Sul.

Congreso; VII Congreso Brasileiro de Tecnología Enzimática - Enzitec 2006; 2006

Universidad de Caxias do Sul

Abstract a-L-rhamnosidase (aR; EC 3.2.1.40), which hydrolyses a-glicosidic bonds, releases rhamnose from glycosides, glycolipids and other natural products. aR from Aspergillus terreus CECT 2663 was covalently immobilized, via glutaraldehyde, on Polyaniline (PANI), chemically synthesized on the internal surface of silicone tubing (600 by 3 mm). The immobilized enzyme properties were investigated by circulating 1.75 mM p-nitrophenyl a-L-rhamnoside throughout the column. The best flow speed using 6.5 mL of circulating substrate was found to be 2 ml.min-1. The specific activity retention was 17 % of that found for the free enzyme; optimal pH and temperature were 7 and 70°C, respectively, whereas the apparent Km and Vm were 0.49 mM and 0.085 hkat cm-1, respectively. The apparent kinetic constant Km was slightly higher that estimated for the free enzyme (0.30 mM), which suggests that the microenvironment surrounding the immobilized enzyme did not change significantly the catalytic action of the immobilized enzyme compared to that of the free enzyme. This reactor can be continuously used in biotechnological applications allowing ease of automation and control.