Mesoporous alginate/silica biocomposites for enzyme immobilisation

Alginate/silica biocomposites were synthesised by impregnation of mesoporous silica particles with alginic acid solution, followed by Ca2+-induced biopolymer gelation. They consist of alginate trapped in the open macroporosity of the silica network, whose porous structure is maintained, as indicated by X-ray diffraction and nitrogen sorption measurements. beta-galactosidase enzymes incorporated in the initial biopolymer solution maintain their catalytic activity towards 4-nitrophenyl-beta-D-galactopyranoside hydrolysis. When compared to the pure Ca-alginate gel, the biocomposites exhibit a better stability upon ageing, limiting enzyme leaching. (C) 2003 Acaddmie des sciences. Published by Editions scientifiques et medicales Elsevier SAS. All rights reserved.