Immobilization of α-amylase on gum acacia stabilized magnetite nanoparticles, an easily recoverable and reusable support

• Immobilization of α-amylase, at room temperature, onto gum acacia stabilized magnetite nanoparticles is reported.
• The synthesis of the enzyme carrier is fast and is carried out in a single step.
• The immobilization is found to increase the catalytic rate by twofold in comparison to the free enzyme.
• The immobilization also facilitates the reuse of amylase for six cycles with 30% of loss in the initial activity.
• At higher temperature, the immobilized enzyme exhibits higher enzyme activity relative to the free enzyme.

In this work, α-amylase is immobilized, using glutaraldehyde, onto magnetite nanoparticles prepared using gum acacia as the steric stabilizer (GA-MN), for the first time. The immobilization of amylase to GA-MN is very fast and the synthesis of GA-MN is very simple. The use of GA enables higher immobilization of α-amylase (60%), in contrast to the unmodified magnetite nanoparticles (∼20%). The optimum pH and temperature for maximum enzyme activity for the immobilized amylase are identified to be 7.0 and 40 °C, respectively, for the hydrolysis of starch. The kinetic studies confirm the Michaelis–Menten behavior and suggests overall enhancement in the performance of the immobilized enzyme with reference to the free enzyme. Similarly the thermal stability of the enzyme is found to increase after the immobilization. The GA-MN bound amylase has also been demonstrated to be capable of being reused for at least six cycles while retaining ∼70% of the initial activity. By using a magnetically active support, quick separation of amylase from reaction mixture is enabled. The catalytic rate of amylase is actually found to enhance by twofold after the immobilization, which is extremely advantageous in industry. At higher temperature, the immobilized enzyme exhibits higher enzyme activity than that of the free enzyme.

In this work, α-amylase is covalently immobilized onto gum acacia stabilized magnetite nanoparticles (GA-MN), for the first time, as a means of providing faster, continuous catalysis and repeated recovery of α-amylase. The immobilization of amylase to GA-MN is very fast and the synthesis of GA-MN is very simple. The catalytic rate of amylase is actually found to enhance by twofold after the immobilization, which is extremely advantageous in industry. The immobilized enzyme can be efficiently recycled for six cycles.Figure optionsDownload as PowerPoint slide