CANADIAN JOURNAL OF CHEMICAL ENGINEERING, vol.100, no.12, pp.3575-3587, 2022 (SCI-Expanded)
The 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 a-glucosidase (a-G) immobilization within p(NIPAM) cryogel (a-G@p(NIPAM)) was carried out under the storage conditions of enzymes, generally similar to -20 degrees 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 degrees 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 degrees C for a-G@p(NIPAM) cryogel system. Interestingly, the optimum working conditions were attained as 25 degrees C and pH 6.8 with higher activity, 98.4% +/- 0.2% for the prepared a-G@p(NIPAM) cryogel system. The reuse and storage stability studies revealed that the prepared a-G@p(NIPAM) cryogel system is more effective than the native a-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 K-m and V-max of native a-G enzyme and a-G@p(NIPAM) cryogel system were calculated by non-linear Lineweaver-Burk plot equations.