Chitosan-tethered poly(acrylonitrile-co-maleic acid) hollow fiber membrane for lipase immobilization

A protocol Was used to prepare a dual-layer biomimetic membrane is support for enzyme immobilization by tethering chitosan on the surface of poly(acrylonitrile-co-maleic acid) (PANCMA) ultrafiltration hollow fiber membrane in the presence of 1-ethyl-3(dimethylaminopropyl) carbodiimide hydrochloride (EDC) N-hydroxylsuccin-imide (NHS), The chemical change of the chitosan-modified PANCMA membrane surface was confirmed with Fourier transform infrared spectrosopy and X-ray photoelectron spectroscopy. Lipase from Candida rugosa was immobilized oil this dual-layer biomimetic membrane using glutaraldehyde (GA), and on the nascent PANCMA membrane using, EDC.NHS as coupling agent. The properties of the immobilized enzymes were assayed and compared with those of the free one. It was found that both the activity retention of the immobilized lipase and (lie amount of bound protein on the dual-layer biomimetic membrane (44.5%,, and 66. 5 mg m(3)) were higher, than those oil the nascent PANCMA membrane (33.9% and 53.7mg/m2). The kinetic parameters of the free and immobilized lipases, K-m and F-max were also assayed. The K-m values were similar for the immobilized lipases. while (the F-max value of the immobilized lipase oil the dual-layer biomimetic membrane was higher than that on the nascent PANCMA membrane Results indicated that the PII and thermal stabilities of lipase increased upon immobilization. The residual activity of the immobilized lipase after 10 uses was 53% oil the duallayer biomimetic membrane and 62% on the nascent PANCMA membrane. (c) 2005 Elsevier Ltd. All rights reserved.