Lipase immobilization for catalytic applications obtained using fumed silica deposited with MAPLE technique

tLipases are enzymes used for catalyzing reactions of acylglycerides in biodiesel production from lipids,where enzyme immobilization on a substrate is required.Silica nanoparticles in different morphologies and configurations are currently used in conjunction withbiological molecules for drug delivery and catalysis applications, but up to date their use for triglycerideshas been limited by the large size of long-chain lipid molecules.Matrix assisted pulsed laser evaporation (MAPLE), a laser deposition technique using a frozen solu-tion/suspension as a target, is widely used for deposition of biomaterials and other delicate molecules.We have carried out a MAPLE deposition starting from a frozen mixture containing fumed silica and lipasein water. Deposition parameters were chosen in order to increase surface roughness and to promote theformation of complex structures. Both the target (a frozen thickened mixture of nanoparticles/catalyst inwater) and the deposition configuration (a small target to substrate distance) are unusual and have beenadopted in order to increase surface contact of catalyst and to facilitate access to long-chain molecules.The resulting innovative film morphology (fumed silica/lipase cluster level aggregation) and the lipasefunctionality (for catalytic biodiesel production) have been studied by FESEM, FTIR and transesterificationtests.