Study On The Immobilization Of Cellulase Using Polysulphone Membrane And Reactor

Celluloses are the most abundant reproducible biomass. It is very important to make use of celluloses for solving the energy crisis, food stuff and environmental problems.Cellulase is necessary for using celluloses, but the high cost baffle the development of saccharification technology. The technology of enzyme immobilization make it possible for its advantages.This paper covers the research work in the following aspects: the method of immobilized cellulase, the changes in properties of immobilized cellulase and a simple enzymatic membrane reactor. Cellulase was immobilized on the polysulphone membrane by means of cross-linking and filtration with pressure. The experiment carried the research on the effects of the concentration of cellulase, the concentration of glutaraldehyde, diferent coupling time, and filtration time immobilized cellulase with two targets: activity, and protein binding capacity. Then the optimized conditions for cellulase immobilization were obtained: cellulase 1.25mg·ml^-1, the concentration of glutaraldehyde 7.0%, diferent coupling time 0.5h, and filtration time 2.0h. The maxmium loading density is 0.131mg·cm^-2 and reaction rate is 1.305μmol·cm^-2·min^-1 on the optimum conditions.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.The results of the experimenton the property of immobilized cellulase porved that the optimal pH was 3.6, the optimal temperature was 60℃,K_m of immobilized cellulase was 26.853 g·L^-1.The thermal stability, the operational stabilities and the stability for reservation of immobilized cellulase were improved considerably. Meanwhile the practical property of immobiled enzyme was measured by simple enzyme reactor on optimum immobiled condition. The results shows:the enzyme reactor has good separation performance but the membrane flux is much smaller.The research work that has been done in this paperp rovides necessary experimental and theoretical base for the following two aspects:the further development of immobilized in good quality and suitable for industrial production and the research enzyme reaction process.