Thermo‐responsive macroporous p(NIPAM) cryogel affords enhanced thermal stability and activity for ɑ‐glucosidase enzyme by entrapping in situ

Abstract

AbstractThe concept of using a macroporous thermo‐responsive poly(N‐isopropylacrylamide) (p(NIPAM)) polymer matrix for enzyme immobilization having lower critical solution temperature (LCST) is rationalized by the availability of the many compartments (pores) to entrap enzymes to operate within pores of three‐dimensional matrix providing special environmental conditions. Therefore, the ɑ‐glucosidase (ɑ‐G) immobilization within p(NIPAM) cryogel (ɑ‐G@p(NIPAM)) was carried out under the storage conditions of enzymes, generally ~ −20°C to afford the unnecessary loss of enzyme functionality in comparison to the other enzyme entrapment methods. The LCST value for the prepared p(NIPAM)‐based cryogels was determined as 34.8 ± 1.4°C. The immobilization yield, immobilization efficiency, and activity recovery% values were calculated as 89.4 ± 3.1, 66.2 ± 3.3, and 74.0% ± 3.3%, respectively, at pH 6.8 and 37°C for ɑ‐G@p(NIPAM) cryogel system. Interestingly, the optimum working conditions were attained as 25°C and pH 6.8 with higher activity, 98.4% ± 0.2% for the prepared ɑ‐G@p(NIPAM) cryogel system. The reuse and storage stability studies revealed that the prepared ɑ‐G@p(NIPAM) cryogel system is more effective than the native ɑ‐G enzyme; for example, it showed at least 80% activity after the fifth usage and provided higher activity up to a 10‐day room temperature storage time. Moreover, the kinetic parameters such as Km and Vmax of native ɑ‐G enzyme and ɑ‐G@p(NIPAM) cryogel system were calculated by non‐linear Lineweaver–Burk plot equations.