Comparison of the immobilization of lipase from Pseudomonas fluorescens on divinylsulfone or p-benzoquinone activated support.

NiZnFe2O4 superparamagnetic nanoparticles were coated with silica by impregnation with tetraethoxysilane (TEOS) and further activated with divinylsulfone (DVS) and p-benzoquinone (BQ) for covalent immobilization lipase from Pseudomonas fluorescens (PFL), producing the biocatalysts TEOS-NANO-DVS-PFL and TEOS-NANO-BQ-PFL. The optimal conditions for enzyme immobilization were found to be pH 7 and 0.1 M of both activating reagents. PFL was also immobilized on TEOS nanoparticles without any activation as a reference (TEOS-NANO-PFL). Results indicated that TEOS could be released from the nanoparticles at alkaline pH value. Optimal TEOS-NANO-PFL exhibited a recovered activity of 55% and a t1/2(60°C) of just over 150 min; while TEOS-NANO-DVS-PFL showed 82% of activity recovered and t1/2(60°C) of 225 min; being the TEOS-NANO-BQ-PFL the biocatalyst offering the best results (89% of recovered activity and a half-life over 1440 min), the maximum enzyme load was ≈300 U/g.