Immobilisation Of Enzyme On Hierarchically Ordered Macroporous/Mesoporous Material And Its Catalytic Application

Hierarchically ordered macroporous/mesoporous materials,which have advantages of good mass transfer,large specific surface area,are novel candidates as supports for enzyme immobilization.In this paper,hierarchically ordered macroporous/mesoporous silica and alumina materials were used as supports,and the immobilized lipase was for the preparation of Glycerol Carbonate.The details were summarized as follows:?1?The preparation of hierarchically ordered macroporous/mesoporous silica?3DOM/m-S?material and the kinetic study of immobilized lipase.3DOM/m-S was prepared through the dual templating method with polystyrene?PS?colloidal crystals as the hard template and amphiphilic triblock copolymers?P123?as the soft template.The SEM and DLS results showed that the hard template was hierarchically ordered and the size was homogeneous.As shown in SEM and TEM images,the achieved 3DOM/m-S possessed ordered macropores of 450 nm and ordered mesopores.N₂ adsorption and desorption test results showed the pore size was 5.2 nm,and the specific surface area and pore volume were 245.6 m²/g and 0.4690 cm³/g,respectively.The successful immobilization of CALB was verified by CLSM.Subsequently,the reaction kinetics on esterification of lauric acid with octyl alcohol using CALB@3DOM/m-S as catalyst was studied.Comparative studies using different solvents having hydrophobicity?log p?values revealed that the esterification reaction was favoured in hydrophobic solvents.The kinetics of the esterification reaction conformed with the so-called Ping-Pong Bi-Bi mechanism with alcohol inhibition.The kinetics constants were 179.8 mM,163.8 mM and 54.41 mM.?2?The preparation of hierarchically ordered macroporous/mesoporous alumina?3DOM/m-Al?material and its catalytic performance.The achieved 3DOM/m-Al possessed ordered macropores and mesopores,which is convenient for the transportion of object molecular.The successful immobilization of enzyme was verified by CLSM.Three different commercial enzymes?CALB,PGA,NHase?were covalent bonding to the amino-functional carriers.For the immobilized method,the optimal concentrations of GA were 1.2 wt%,1.6 wt%and 0.8 wt%and the optimal concentrations of enzymes were 400mg/g_support,90 mg/g_support and 270 mg/g_support.Compared with free enzymes,the immobilized enzymes exhibited better thermal and reusability stabilitie.?3?The preparation of Glycerol Carbonate using CALB@3DOM/m-S as catalyst.This work describes the synthesis of glycerol carbonate glycerol via an enzymatic transesterification reaction using dimethyl carbonate as co-substrate.The reaction parameters of GC were optimized and the optimum conditions were as follows:molar ratio of DMC to glycerol 10:1,the amount of the molecular sieve 0.4 g,temperature 50?,the dosage of enzyme 30 g/L.After 24 hours,the maximum GC obtained could reach 89%.After 6 successive batch reactions,60%of the GC yield was obtained.Compared to Novozyme 435,CALB@3DOM/m-S exhibited better reusability stabilitie.