Preparation and characterization of ?-amylase-immobilized thermal-responsive composite hydrogel membranes

✍ Scribed by Sun, Yi-Ming ;Chen, Jyh-Ping ;Chu, Ding-Hsin

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 190 KB
• Volume: 45
• Category: Article
• ISSN: 0021-9304
• DOI: 10.1002/(sici)1097-4636(199905)45:2<125::aid-jbm7>3.0.co;2-b

✦ Synopsis

Composite hydrogel membranes of crosslinked poly(N-isopropylacrylamide-co-N-acryloxysuccinimide-co-2-hydroxyethyl methacrylate) [P(NIPAAm-NAS-HEMA)] with starch, as a macropore forming agent, on nonwoven polyester was prepared. The membranes could swell and de-swell around the characteristic lower critical solution temperature (LCST) of poly(N-isopropylacrylamide) (PNIPAAm). It was demonstrated that the presence of macropores in the membranes could improve the immobilization efficiency as well as lead to a short responding time upon temperature change across the LCST. Immobilized ␣-amylase could retain as high as 33% of the activity of the free enzyme with a loading level of 0.60-0.65 mg/cm 2 when the membrane preparation and enzyme immobilization conditions were optimized. The half time (T 0.5 ) for the swelling or de-swelling response of the gel phase within the membranes was less than 2 min, and the 90% time (T 0.9 ) was less than 6 min. The permeability for maltose through the membranes could change as much as 4.9-fold when the temperature was raised above or reduced below the LCST.