Preparation of Novel Poly(hydroxyethyl methacrylate-co-glycidyl methacrylate)-Grafted Core-Shell Magnetic Chitosan Microspheres and Immobilization of Lactase

Abstract

Poly(hydroxyethyl methacrylate-co-glycidyl methacrylate)-grafted magnetic chitosan microspheres (HG-MCM) were prepared using reversed-phase suspension polymerization method. The HG-MCM presented a core-shell structure and regular spherical shape with poly(hydroxyethyl methacrylate-co-glycidyl methacrylate) grafted onto the chitosan layer coating the Fe3O4 cores. The average diameter of the magnetic microspheres was 10.67 μm, within a narrow size distribution of 6.6–17.4 μm. The saturation magnetization and retentivity of the magnetic microspheres were 7.0033 emu/g and 0.6273 emu/g, respectively. The application of HG-MCM in immobilization of lactase showed that the immobilized enzyme presented higher storage, pH and thermal stability compared to the free enzyme. This indicates that HG-MCM have potential applications in bio-macromolecule immobilization.

Enhancing catalytic performance of laccase via immobilization on chitosan/CeO 2 microspheres

“…Chitosan-based materials are used as supports in various forms, such as powder, flake, and gel, with different geometrical configurations for immobilization of several enzymes [15]. In the last few decades, chitosan containing magnetic supports, especially magnetic microspheres, were investigated for enzyme immobilization using physical and chemical immobilization techniques [16][17][18][19].…”

Immobilization of Enzymes on 2‐Hydroxyethyl Methacrylate and Glycidyl Methacrylate Copolymer Brushes

“…The mass of the PHEMA brushes polymerized for 30 min in a wet state (including water) and a dry state was around 5.4 and 3.9 mg cm À2 , respectively (see the Supporting Information). It is slightly lower than that ( % 50 %) of the PHEMA/GMA hydrogel with a similar monomer ratio, [30] probably owing to the restriction of the anchored polymer chains at one end and different characterization methods. After polymerization for 100 min, the wet mass and thickness of the H/G brushes reached 7.8 mg cm À2 and 82 nm, respectively.…”

“…However, the percentage of active lysozymes decreased as the P(HEMA-co-GMA) chain was extended (Figure 4a). [30] One of the possible reasons is that the enzyme conformation is more severely changed at a higher grafting density. [30] One of the possible reasons is that the enzyme conformation is more severely changed at a higher grafting density.…”

“…[30] The amount of immobilized lysozyme can be easily tuned by varying the length of the second block as well. The PHEMA block on the bottom (Scheme 1) serves as a spacer to give flexibility to the tethered enzymes and prevent adsorption of contaminants in the environment.…”

“…The copolymerization of HEMA and GMA in the second block is used to reduce the density of reactive sites and enhance the brush flexibility and hydrophilicity, which are helpful to enhance the activity and stability of the tethered enzymes. [30] The amount of immobilized lysozyme can be easily tuned by varying the length of the second block as well.…”