Investigation On The Preparation And Properties Of Immobilized Cellulase

As one of the important components of modern bioengineering and biotechnology, Immobilized enzyme technique has been widely used in the fields of industry, medicine, analytical & separation techniques, chemical synthesis, etc. This paper covers the research work in the following aspects: the carrier of Immobilized enzyme, the methods of immobilized cellulase, the changes in properties of immobilized cellulase and a kinetics model of immobilized cellulase.Cellulase was immobilized on the starch-g-poly(acrylonitrile/acrylamide) copolymers carrier by adsorption. At the same time, cellulase was also immobilized onto 4-amiono-benzene sulfonylethyl starch graft copolymers carrier by means of diazotization. The experiment carried the research on the effects of different coupling time, pH of buffer, the amount of cellulase and ionic strength on immobilized cellulase with four targets: activity, specific activity, protein binding capacity and activity recovery. Some characters of free cellulase, such as optimum temperature, optimum pH, Michaelis-Menten constant, the thermal stability, the operational stabilities and the stabilities for reservation have been studied through the comparison of immobilized cellulase by adsorption and immobilized cellulase by covalent coupling. The results of the experiment on the property of immobilized cellulase prove that the optimal pH was 6.6, the optimal temperature was 50℃, Km of immobilized cellulase by adsorption was 0.208g/L and Km of immobilized cellulase by covalent coupling was 0.135g/L. The thermal stability, the operational stabilities and the stability for reservation of immobilized cellulase were improved considerably.A kinetics model of immobilized cellulase has been established, which took into account inner diffusion limitation and product competition inhibition. Based on the kinetics model, the effects of Thiele modulus, product competition inhibition, and macro-substrate-concentration on substrate distribution in the enzyme particle were investigated, and effectiveness factors were also obtained.The research work that has been done in this paper provides necessary experimental and theoretical base for the following two aspects: the furtherdevelopment of Immobilized enzyme that is in good quality and suitable for industrial production and the research on immobilized enzyme reaction process.