Comparison between different inorganic supports for the immobilization of amyloglucosidase and α-amylase to be used in enzyme reactors in flow-injection systems: Part I. Hydrolysis of maltose, maltooligosaccharides and soluble starch

Abstract

Amyloglucosidase was immobilized on twelve different inorganic supports by silanization with aminopropyltriethoxysilane followed by glutaraldehyde activation. Two of the supports were alumina based and were also functionalized with polyethylenimine (PEI) followed by glutaraldehyde activation. The different enzyme immobilized supports were packed in identical reactors (30 μl) and compared with respect to optimum pore size, surface area, immobilization efficiency and enzyme activity for three substrates: soluble starch, maltooligosaccharides and maltose. A comparison of five silanized controlled-pore glasses (CPG) with different pore sizes resulted in the highest immobilization efficiency on the support with a pore size of 170 Å and a surface area of 150 m 2 g −1. A comparison of all the silanized enzyme supports again gave the highest immobilization efficiency on 170 Å CPG, but the highest enzyme activity was obtained on a new support, Micropil A, with a pore size of 300 Å and a surface area of 100–150 m 2 g −1. The functionalization of the alumina supports with aminopropyltriethoxysilane proved to be superior to that with PEI.