Secondary conformational analysis via
Circular
Dichroism (CD) and Amide-I FTIR was
applied to preparations of Candida
antarctica Lipase B (CALB), subtilisin
Carlsberg, and the Lipase from Thermomyces lanuginosus (TLL) on fumed silica to
confirm that the “hardness” and packing
density of the enzymes on the solid fumed
silica nanoparticle surface can be used to rationalize the variable enzyme-dependent
changes of catalytic competency with
surface coverage. “Soft” enzymes should
be immobilized at a surface coverage where
enzyme-enzyme interactions predominate
thereby preventing detrimental structural
changes caused by enzyme-support interactions, while “hard” enzymes can be immobilized at
low to intermediate surface coverage with
good catalytic performance. Multi-layered coverage reduces the superficial average catalytic performance in all cases due
to mass transfer limitations.
