Immobilization of α‐amylase on reactive modified fiber and its application for continuous starch hydrolysis in a packed bed bioreactor

Abstract

In this study, the enzyme α‐amylase was immobilized on reactive modified poly (ethylene terephthalate) fiber. The activities of free α‐amylase and immobilized α‐amylase were compared in a batch starch hydrolysis system. Optimum pH and Michaelis–Menten constants were determined for both free α‐amylase and immobilized α‐amylase. The immobilization shifted the optimum pH to a higher level. The Michaelis–Menten constant values (Km) of the immobilized α‐amylase and free α‐amylase were obtained as 11.94 and 6.61 mg/mL, respectively. The experiments indicated that the immobilization increased the thermal stability of the α‐amylase. The immobilized α‐amylase, easily separated from the reaction media, could be used effectively for 15 cycles with 65% retention of the initial activity. Moreover, the immobilized α‐amylase was effectively used in packed bed bioreactor for continuous starch hydrolysis throughout 6.5 h without loss of activity. Different starches (e.g., potato and wheat) were hydrolyzed by the immobilized α‐amylase in continuous process. The results indicate a potential use of this immobilized enzyme system for the construction of packed bed bioreactors to be used in the hydrolysis of the starch.

Immobilization of α-amylase on eggshell membrane and Ag-nanoparticle-decorated eggshell membrane for the biotransformation of starch

“…The increase of K m and decrease of V max after immobilization showed the decrease of affinity between enzyme and substrate, which was consistent with previous reports [3,6,21,22]. This could be explained by the diffusional limitation of the substrate due to steric hindrance from the immobilizing supports, which caused lower accessibility of substrate to the active sites of the immobilized enzymes or conformational changes of the enzyme occurring in the immobilizing process which re sulted in a lower possibility of substrate-enzyme complex formation [3,8,20]. Additionally, the K m value for a-amylase immobilized on AgNP/ESM was larger than that on ESM.…”

“…The optimal temperature was 55°C for both free and immobilized enzymes. The unchanged optimal temperature after immobilization was also reported in previous studies [9,19,20]. When temperature was below 55°C, a-amylase immobilized on AgNP/ESM retained more of its activity relative to free and ESM-immobilized enzymes.…”

“…Figure shows the reusability of the immobilized α‐amylases exhibited as plots between the reuse number and relative activity. The activity of immobilized enzymes decreased gradually with the increase of reuse number, which might be due to detachment of the enzyme molecules from the immobilizing supports or slow deactivation of the enzyme during repeated handling . After six uses, the residual activities were 70.07 and 82.44% for α‐amylases immobilized on ESM and AgNP/ESM, respectively.…”

An Accessible Method to Improve the Stability and Reusability of Porcine Pancreatic α-Amylase via Immobilization in Gellan-Based Hydrogel Particles Obtained by Ionic Cross-Linking with Mg2+ Ions

“…However, it is important to be careful with random immobilization techniques as they can also lead to a decrease in the catalytic activity and stability of the enzymes. Immobilization techniques must be used to stabilize enzymes against inhibitors, preventing aggregation, autolysis, or proteolysis [ 23 , 24 , 25 , 26 ]. The immobilization of α-amylase can also modify the enzyme selectivity and specificity, reduce inhibitions, or be coupled to purification [ 15 , 27 , 28 , 29 , 30 ].…”