In situ immobilization of commercial pectinase in rigid polyurethane foam and application in the hydrolysis of pectic oligosaccharides

The commercial pectinase (Rohapect (R) DA6L) from Aspergillus niger was successfully in situ immobilized in rigid polyurethane foam (RFPU), achieving a yield of immobilization of 178.64%. The optima reaction conditions for free and immobilized pectinase were pH 3.5 and 37 degrees C and pH 4.5 and 55 degrees C, respectively. During the evaluation of storage stability of immobilized derivative at 4 degrees C, a hyperactivation of enzyme activity was observed, with an increase of 98% on the initial activity after 229 days of storage. The study of thermal stability showed that the immobilization exerted a protective effect to the enzyme submitted to high temperatures, probably due to a result of the microenvironment created inside the RFPU. The kinetic parameters showed that the immobilization process did not change the affinity of the enzyme by the substrate. The immobilized pectinase in RFPU was reused consecutively by 6 catalytic cycles in the hydrolysis of pectic oligosaccharides, keeping 35% of its initial activity. Due to the good performance of the enzymatic derivative, this presents a potential alternative to be used in the conception of industrial reactors. (C) 2015 Elsevier B.V. All rights reserved.