Adsorption of Ps. Fluorescens lipase on beta-cyclodextrin nanosponges results in enzyme stabilization and modulates its catalytic and structural properties

Exploitation of enzymes in industrial processes is economically advantageous only in the presence of high reaction yields and high recycling rates. Enzyme immobilization on suitable supports allows their use under continuous-flow conditions and often increases their stability and limits inhibition effects due to reaction products or components of the reaction mixture. In the present work, we have checked the activity and structural stability of lipase , from Pseudomonas fluorescens adsorbed on newly synthesized cyclodextrin-based nanosponges (characterised by distinct chemical composition and cross-linkage degree). Once the immobilization protocol optimized, a comparison between some chemical and structural features of the absorbed and solubilised lipase was carried out. In particular, the effect of temperature, pH changes and organic solvents (methanol) on the enzyme structure and function have been investigated. Our data show that cyclodextrin-based nanosponges stabilize Ps. fluorescens lipase, as the enzyme was still active after 66 days incubation at T~18°C. In addition, unlike the solubilized enzyme, the adsorbed lipase was active at T>40°C, at pH 5 and after 24h-incubation with 70% v/v methanol (13% residual activity).