| Summary: | 碩士 === 國立成功大學 === 化學工程學系碩博士班 === 96 === Electrospinning is a novel process to produce fibrous membranes with nanoscale diameters and properties of high specific surface area as well as porous structure, so electrospun nanofibrous membranes are excellent for filtration application, drug delivery, tissue engineering scaffold and enzyme immobilization.
In this study, nanofibrous membrane, made by poly(acrylonitrile-blending-maleic acid anhydride) (PAN-b-MA), contained anhydride groups for immobilizing cellulase from Aspergillus niger. The average diameter of 150~300 nm was observed from the nanofiber by FESEM and covalent bond formation between enzyme molecule and nanofibrous membrane was confirmed by using FTIR. When the blending ratio of PAN and maleic anhydride ratio was given as 1:1 (w/w), the immobilization efficiency of nanofibrous membrane was superior. The loading efficiency of immobilized enzyme on nanofiber was about 40%, and the specific activity was 450 U/g-material.
The biocatalytic efficiency of immobilized cellulase was examined for carboxymethyl cellulose (CMC) hydrolysis for determining the optimal immobilization conditions in appropriate enzyme concentration of 10 wt%, pH value of 4.6, and reaction time of 90 min at 60℃. Under the optimal immobilization condition, the immobilized enzyme performed well for CMC hydrolysis at reaction temperature of 50℃ but independent of pH value. In addition, the immobilized cellulase demonstrated better thermal stability than free enzyme at higher temperature. Beside, it retained 60% of its initial activity after six repeated batches of reaction.
PAN-b-MA nanofibrous membrane was prepared by electrospinning and successfully used as the support for cellulase immobilization, and it is the potential reusable biocatalyst for hydrolyzing crystalline cellulose.
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