title: Enzyme-immobilized clay nanotube-chitosan membranes with sustainable biocatalytic activities.
abstract: We have developed a simple and effective strategy to prepare an enzymatic membrane by the admixing of a halloysite clay nanotube-lipase complex and a chitosan solution. The loading of 3 wt% lipase into the lumen of halloysite clay nanotubes was enhanced with an electrostatic interaction. 10 wt% of lipase-nanotubes were dispersed in an aqueous chitosan solution and cast as a coating. The enzymatic chitosan-halloysite membranes displayed increased pH, temperature stability and long-term usability for the catalytic decomposition of lipids: 90% of the initial activity was preserved at 80 °C, 70% of the functionality remained at the high pH of 9, and 85% of the activity was sustained after ten continuous cycles of use. The placement of the second antimicrobial enzyme-lysozyme at the outer surface of the clay nanotubes allowed for a synergistic increase in the activity of the composite antibacterial formulation. The lipase/lysozyme-co-immobilized clay nanotube-chitosan membranes are promising in anti-biofouling applications.
authors.affiliation: State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China. yanxh@ipe.ac.cn and School of Chemistry and Environmental Engineering, Harbin University of Science and Technology, Harbin 150080, China.
authors.forename: Jiajia
authors.identifier: http://orcid.org/0000-0002-5801-4769
authors.initials: J
authors.lastname: Sun
authors.affiliation: Institute for Micromanufacturing and Biomedical Engineering Program, Louisiana Tech University, Ruston, LA 7172, USA. ylvov@latech.edu.
authors.forename: Raghuvara
authors.initials: R
authors.lastname: Yendluri
authors.affiliation: State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China. yanxh@ipe.ac.cn and University of Chinese Academy of Sciences, Beijing 100049, P. R. China.
authors.forename: Kai
authors.initials: K
authors.lastname: Liu
authors.affiliation: School of Chemistry and Environmental Engineering, Harbin University of Science and Technology, Harbin 150080, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Institute for Micromanufacturing and Biomedical Engineering Program, Louisiana Tech University, Ruston, LA 7172, USA. ylvov@latech.edu and I. Gubkin Russian State University of Oil and Gas, Moscow 119991, Russia.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Lvov
authors.affiliation: State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China. yanxh@ipe.ac.cn.
authors.forename: Xuehai
authors.initials: X
authors.lastname: Yan