| Immobilization of lipase for catalyzing in organic solvents is a novel technique rapidly developed in recent years. The stability of the enzyme was significantly improved after immobilization. In this thesis, The lipase from Candida rugosa was immobilized in organic solvent, optimized condition and preparation for immobilization, activity and stability of the immobilized lipase and kinetics of enzymatic reactions were studied.The experiment first filtered eight kinds of carriers, selected macroporous adsorptive resin AB-8 as the carrier immobilizing lipase. The immobilization methods, carriers and conditions were studied. The studies on immobilization conditions showed that the optimal concentration of buffer was 7.2, the best temperature was 30℃, the the optimal reaction time and ratio of carrier to lipase, were 1h and 10:1 respectively.The effects of various conditions on activity of the immobilized lipase were investigated taking the esterification of lauric acid and lauryl alcohol in organic solvents as a model reaction. It was found that isooctane was the best solvent. The optimal pH for preparation of the immobilized lipase was 7.2, and the optimal reaction rotate was 180rpm, initial water content was 50μL. The reaction was stirred with for 24h at 30℃, esterification rate of lauric acid was 81%. The characteristics of immobilized lipase was investigated. The results showed it was more stable than free lipase in high temperature, the residual activity of immobilized lipase and free lipase were 68% and 32% respectively. After being reused for 10 cycles, the remaining activity of immobilized lipase was about 50.8%. After 35 days reserved in 4℃, 30℃, and 40℃, the residual activities of immobilized lipase were 74.3%, 51.6%和43.0% respectively.The kinetics of esterification of lauric acid and lauryl alcohol catalyzed by the immobilized lipase in isooctane was investigated. The reaction was found to follow the Ping-Pang Bi-Bi mechanism with an inhibition by alcohol. The kinetic parameters under the optimal reaction conditions were obtained. The maximum rate (Vmax) was 0. 089 mmol.min-1.g-1. The Michaelis constants of lauric acid (Km(LA)) and lauryl alcohol (Km( DL)) were 21.4mM and 59.6mM, respectively.
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