Improved biochemical characteristics of crosslinked β-glucosidase on nanoporous silica foams

Large mesoporous cellular foam (LMCF) materials were synthesized using the microemulsion templating route. For the enzyme stabilization, β-glucosidase was immobilized onto mesocellular silica foams (MCFs) in a simple and effective way, a process achieved using enzyme adsorption followed by glutaraldehyde (GA) crosslinking. This resulted in the formation of crosslinked enzyme aggregates (CLEAs) of nanometer scale. The structural and chemical properties of these prepared materials were characterized by TG, CPMAS NMR and nitrogen adsorption measurements. The crosslinked immobilizates retained activity over wider ranges of temperature and pH than those of the free enzyme. Kinetic parameter (Km) of the immobilized β-glucosidase is lower than that of its free counterpart. The resulting CLEA was proved to be active and recyclable up to 10 cycles without much loss in activity. This demonstrates its prospects for commercial applications. The immobilizate exhibited enhanced storage stability characteristics than the native enzyme. In contrast to adsorbed GL and covalently bound glucosidase, the resulting crosslinked enzyme aggregates (CLEAs) showed an impressive stability with high enzyme loadings.

Figure optionsDownload as PowerPoint slideHighlights
► As a possible application of mesocellular silica foams (MCFs), catalytically active crosslinked enzyme aggregrates (CLEA's) of β-glucosidase was developed.
► Immobilization broadened the pH optimum and the temperature dependant activity profile of the free β-glucosidase.
► The Km values of the crosslinked β-glucosidase was higher than those of the free enzyme.
► CLEA-GL exhibited superior operational stability and good storage stability.
► The results obtained are of considerable interest for the possible future application of the immobilized enzyme in the wine-making industry.