Superporous neutral, anionic, and cationic cryogel reactors to improved enzymatic activity and stability of α-Glucosidase enzyme via entrapment method

Abstract

Although enzymes are unique catalysts with highest selectivity for desired products, their cost, poor stability, and delicate reaction condition are the main drawbacks. To circumvent these obstacles and render viable enzymatic reactions with increased durability and stability, enzymes are generally immobilized in very different substrates. Therefore, herein, α-Glucosidase from Saccharomyces cerevisiae (α-Glu) as a model enzyme was entrapped within neutral, anionic and cationic synthetic cryogels such as poly(Acrylamide) (α-Glu@p(AAm)), poly(2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid) (α-Glu@p(AMPS)), and poly(3‐acrylamidopropyltrimethyl ammonium chloride) (α-Glu@p(APTMACl)) during the synthesis process. The prepared α-Glu@p(AAm), α-Glu@p(AMPS), and α-Glu@p(APTMACl) cryogels were used as reactor and found to main their enzymatic activity of 80.9 ± 3.5, 61.5 ± 2.2, and 50.9 ± 3.1% with respect to free enzyme at its’ optimum conditions, pH 6.8 and 37 °C, respectively. Interestingly, at harsher pH conditions, it was fond that α-Glu@p(AMPS) cryogels showed 100% activity at pH 8.0, and α-Glu@p(APTMACl) cryogels showed 100% activity at pH 5.0, whereas free α-Glu almost lost its catalytic activity completely at the same pHs. The operational and storage stability studies revealed that the entrapment of α-Glu within cryogels led to much better operational and storage stability than free α-Glu enzyme e.g., more than 50% activity after 10th usage and 10-day storage time at room temperature while almost no activity is attained for free enzyme. The kinetic parameters such as Km and Vmax of α-Glu@cryogel were also calculated by using Lineweaver-Burk plotting method and compared each other and free α-Glu enzyme.