Utilization of a biphasic oil/aqueous cellulose nanofiber membrane bioreactor with immobilized lipase for continuous hydrolysis of olive oil
A simple method is proposed to fabricate a biphasic lipase-immobilized cellulose membrane bioreactor with high enzyme loading and activity retention. This bioreactor was assembled with electrospun cellulose nanofiber membranes that were fixed in a spiral form and wound to increase their specific surface area. To improve the catalytic efficiency of the immobilized enzymes, the supports went through alkaline hydrolysis, NaIO4 oxidation and pentaethylenehexamine modification before covalently binding the lipase. Enzyme loading could reach 28.9 mg/g with the highest activity retention of 44.3 % for the immobilized lipases. The effects of the operational variables, namely the organic phase flow rate, aqueous phase flow rate and substrate concentration, on the performance of this bioreactor were investigated with continuous hydrolysis of olive oil. It was found that under optimum operational conditions, 100 % hydrolysis conversion of olive oil was achieved after 9 organic phase circulations at 10.5 mL/min organic phase flow rate, 600 mL/min aqueous phase flow rate and using a substrate of pure olive oil. Nanofiber membrane bioreactors offer potential as applications for various lipase-catalyzing reactions in industrial productions.
KeywordsCellulose Nanofiber membrane Enzyme immobilization Lipase Biphasic enzyme-immobilized membrane bioreactor
The authors are grateful to the financial support from the Fundamental Research Funds for the Central Universities (Grant no. 2013QNA4090), the National Natural Science Foundation of China (Grant no. 21274126), and the National “Twelfth Five-Year” Plan for Science & Technology Support of China (Grant no. 2012BAI08B01).
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