Mesoporous alginate/silica biocomposites for enzyme immobilisation

Alginate/silica biocomposites were synthesised by impregnation of mesoporous silica particles with alginic acid solution, followed by Ca 2+ -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. β-galactosidase enzymes incorporated in the initial biopolymer solution maintain their catalytic activity towards 4-nitrophenyl-β- d -galactopyranoside hydrolysis. When compared to the pure Ca-alginate gel, the biocomposites exhibit a better stability upon ageing, limiting enzyme leaching.