Enhanced transesterification by immobilized lipase on chitosan／graphene oxide composite membrane bioreactor through pervaporation

• Main Authors: Wen-Chuan Chang, 張文銓
• Other Authors: Chung-Jung Chou
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/55184348557252870623

碩士 === 中原大學 === 化學工程研究所 === 105 === Recently, environmental protection, energy efficiency and carbon reduction are increasingly important in chemical engineering field. Enzyme technology is considered as a viable option in green energy production, including alternative fuel such as biodiesel. The primary principle of biodiesel synthesis is the subsequent hydrolysis and transesterification of vegetable oil by lipase enzyme catalysts. Moreover, combination of membrane fabrication technology, and immobilization enzyme techniques would increase the overall reaction efficiency and cost through better enzyme stability and surface reaction kinetics. In this work, chitosan, and graphene oxide were mixed in proper ratio and casted onto pervaporative polysulfone membrane for immobilization of Candida rugosa lipase for hydrolysis reaction and transesterification of soybean oil. A membrane bioreactor was set up and connected with real time UV-VIS spectroscopy to interrogate the kinetic effects of different CS/GO ratio in composite membranes and optimal temperature. Subsequently, the membrane reactor was challenged with two phase (oil-water-methanol) transesterification reaction for fatty acid methyl ester (FAME) production. The integrity and surface phenotype was observed with scanning electronic microscope (SEM). The results suggested that the graphene oxide doping may affect the affinity of oil toward the composite membrane surface. Results suggested that the lipase immobilized on CS/GO1:0.25 composite membrane in 45℃ exhibited the optimal 96.8% hydrolysis ratio of para-nitrophenyl palmitate (pNPP) among all operational parameters. Next, the transesterification capability of this enzymatic complexed membrane was compared through three different operational modes, including atmospheric vaporization, convective vaporization and pervaporation. The results showed that the convective vaporization and pervaporation modes can improve transesterification ratio to 91.3% and 92.1%, respectively. As result, the reactor design based on chitosan-graphene composite membrane could increase the enzyme stability and kinetics performance of the immobilized lipase, and could be applied to fine chemical production in the future.