The Research Of Lipase Immobilized On Renewable Nanosupports And Its Catalytic Performances

ZnO nanowires were successfully introduced into a macroporous Si O2 by in-situ hydrothermal growth in 3D pores. The obtained composites were characterized by SEM and XRD.1. The obtained composites were used as supports to immobilize Candida antarctica lipase B(CALB) through adsorption. The high specific surface area(233 m2/g) and strong electrostatic interaction resulted that the average loading amount of the composite supports(196.8 mg/g) was 3~4 times of that of macroporous Si O2 and approximate to that of a silica-based mesoporous material. Both adsorption capacity and the activity of the CALB immobilized on the composite supports almost kept unchanged as the samples were soaked in buffer solution for 48 h. The chiral resolution of 2-octanol was catalyzed by immobilized CALB. A maximum molar conversion of 49.1% was achieved with 99% enantiomeric excess of(R)-2-octanol acetate under the optimal condition: a reaction using 1.0 mol/L(R, S)-2-octanol, 2.0 mol/L vinyl acetate and 4.0 wt.% water content at 60 °C for 8 h. After fifteen recycles the immobilized lipase could retain 96.9% of relative activity and 93.8% of relative enantioselectivity.2. ZnO nanowires/macroporous Si O2 composites were used as a new type of microwave absorbing support to immobilize Candida rugosa lipase(CRL). Under microwave irradiation the immobilized lipase was used to catalyze esterification of phytosterol and oleic acid for the synthesis of phytosterol esters. A great improvement of the catalytic activity was found in the systems in which composited Zn O nanowires were present. The microwave absorbing properties of Zn O nanowires has been proved to be helpful for the synergistic effect between microwave irradiation and enzyme catalysis. The immobilized CRL showed higher thermal stability at 55°C under microwave irradiation than conventional heating. A maximum molar conversion of 95.4% under microwave irradiation was achieved under the optimal condition: 0.1 M phytosterol, 0.2 M oleic acid, water activity(aw) of 0.11, reaction temperature at 50 °C and reaction time of 1 h.