Magnetic cellulose beads as support for enzyme immobilization using polyelectrolytes through electrostatic adsorption

Pectinase was immobilized on magnetic regenerated cellulose microspheres using cationic polyacrylamide (CPAM) or polyethyleneimine (PEI) via electrostatic adsorption. PEI-immobilized enzyme (PEI-EMCB) had higher activity (2711 U/g) than CPAM-immobilized enzyme (CPAM-EMCB). The time course of PEI-immobilized enzyme catalytic reaction was similar to the free form. PEI-EMCB reached its maximal activity at pH 4.8, while the optimal pH for CPAM-EMCB was the same with the free form (4.4). CPAM3-EMCB was most tolerant to pH variation, which can be possibly ascribed to the high molecular weight of CPAM3. After immobilization, the optimum temperature for the enzyme declined from 45 °C to different degrees. PEI-EMCB exhibited good storage stability with 67% of the initial activity maintained after 7 days and with moderate reusability. The magnetic properties of the regenerated cellulose beads provided convenience for the immobilized enzyme to be used and recycled. The results indicate a potential route for utilization of cellulose as enzyme support via a simple method.