Functionalized Stober silica as a support in immobilization process of lipase from Candida Rugosa

Lipase from Candida rugosa was immobilized onto modified Stober silica. Modification was made with 3-(2,3-epoxypropoxy)propyltrimethoxysilane and glutaraldehyde. The immobilization process by covalent binding was performed for 1 and 24 h using different concentrations of enzyme solution. The obtained immobilized biocatalysts were subjected to physicochemical characteristics. The characteristics of functional groups (FTIR, 13C CP MAS NMR), thermal stability (TG) and parameters of the porous structure (low temperature N2 sorption) were determined. An elemental analysis was performed to determine the content of nitrogen, carbon and hydrogen. Using a Bradford method the immobilization yield (IY) and amount (P) of lipase loaded onto support were calculated. The obtained systems were also tested to evaluate their catalytic activity in hydrolysis reaction of p-nitrophenyl palmitate (p-NPP) to p-nitrophenol (p-NP). The results confirmed the effectiveness of immobilization process and high hydrolytic activity (2270 U/g) of immobilized biocatalysts.