NMR characterization of the role of silane precursors on the catalytic activity of sol–gel encapsulated lipase

Lipase from Candida rugosa was encapsulated within sol–gel supports prepared by the polycondensation of either tetraethoxysilane or methyltrimethoxysilane, in the presence or absence of polyethylene glycol as an additive. Both the structure and texture of the resulting gels were significantly affected by changing the precursor type in the chemical synthesis. Silica gels and their immobilized enzyme derivatives were characterized by 29Si and 13C nuclear magnetic resonance. The hydrolysis and esterification activities of the encapsulated lipase samples were measured, showing that for ester synthesis they demonstrate similar activity to the free enzyme, but for hydrolysis they demonstrate lower performance.