Studies toward stereoselective bionanocatalysis on gold nanoparticles

As yet, different enzymes were immobilized on gold nanoparticles both through adsorption and covalent binding. However, there is only one evaluation if such immobilization influenced enzyme enantioselectivity, which is an essential parameter in biocatalysis. Therefore systematic studies with enzymes immobilized on gold nanoparticles through covalent binding and embedded through adsorption were performed. Adsorption was not efficient method and it significantly lowered enantioselectivity of enzymes. In turn, covalent binding was in most cases very good method of immobilization, especially for Pseudomonas cepacia lipase, where conversion and enantioselectivity were even slightly better than for native enzyme. It was also evaluated that in case of adsorption size of nanoparticles did not influence enantioselectivity, but in case of covalent binding small nanoparticles gave much better results than big ones.

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► Selected enzymes were immobilized on gold nanoparticles of different kinds and size.
► Kinetic resolution reactions with immobilized enzymes were performed.
► Influence of immobilization on enantioselectivity was determined.
► Enzymes immobilized covalently were as good biocatalysts as native ones.
► The best lipase was reused four times and retained 50% of its catalytic activity.