Functionalized porous ceramic microbeads as carriers in enzymatic tandem systemsTuesday (09.05.2017) 12:40 - 13:00 Room Goethe III Part of:
The feasibility of porous Al2O3/SiO2 microbeads (MBs) as carriers for enzymes used in flow reactor setups for tandem enzymatic reactions is studied. Glucose oxidase (GOx) and catalase (CAT) perform sequential substrate reactions where GOx converts ß-D-glucose to H2O2 using O2 (co-factor) and CAT decomposes H2O2 to H2O and O2. Spherical MBs were fabricated via ionotropic gelation followed by rapid-sintering (1200°C/ 5 min), showing high open porosity (~50 %), high specific surface area (30±5 m2/g) and multi-modal pore sizes (d50 = 79 nm) for envisaged enzyme immobilizations. After activation and amino-silanization, GOx and CAT are successfully immobilized onto MBs applying standard EDC/sulfo-NHS crosslinking reaction. In batch tests at varied pH and temperature, the immobilized enzymes showed advantages towards harsh conditions (pH 2; 70 °C) and demonstrated high activities at neutral pH and room temperature, serving as optimal conditions for flow experiments. Varying flow rates (0.1-6 ml/min) in individual reactor compartments over 24 h, GOx- and CAT-functionalized MBs revealed satisfiable H2O2 conversion rates at 1 ml/min, respectively. In tandem use, produced H2O2 is constantly degraded over time (24 h), maintaining high enzymatic overall performances for two more operation cycles. The presented strategy offers the possibility to be used for other multi-enzyme reaction systems.