SiO₂-Coated Fe₃O₄ Nanoparticle/Polyacrylonitrile Beads for One-Step Lipase Immobilization

Abstract

Nanoscale particle-based enzyme immobilization carries a risk of dissolving or breaking the material when applied. One effective strategy to improve the stability and functionality of this type of nanomaterial is compounding with polymers. In this study, Fe3O4 nanoparticles were synthesized and coated with SiO2, after which magnetic hollow composite beads with nanoscale porous structures, named, lipase/Fe3O4/PAN (L/FP), were fabricated by compounding polyacrylonitrile and SiO2-coated Fe3O4 nanoparticles to immobilize Candida antarctica lipase B (CALB) in one step. Fourier transform infrared spectroscopy, scanning electron microscopy, the Brunauer–Emmett–Teller method, vibrating sample magnetometer measurements, and thermogravimetry analysis were used to analyze the structure of hollow beads. It was found that composite beads retained nanoscale channels and had a larger specific surface area (27.2 m2/g), a higher pore volume (0.09 cm3/g), and better saturation magnetization values (9.8 emu/g) than PAN hollow beads (6.2 m2/g, 0.03 cm3/g, and 0 emu/g, respectively). After optimizing fabrication and immobilization conditions, L/FP showed a high lipase capacity (50 mg protein/g support) at 2 mg/mL lipase, and the immobilized yield was up to 98.4% when the mass ratio of the starting lipase and support was 1.3 (mg lipase/g support). The immobilized lipase in L/FP showed greater thermal stability and resistance to alkali than free CALB. L/FP also had good stability in most organic solvents. In all tested cycles, it also had better reusability (78.4, 47.2, and 23.8% retained activity after 10, 20, and 30 cycles, respectively) in ester hydrolysis than CALB-immobilized Fe3O4 nanoparticles or PAN beads and had higher activity than the commercial immobilized lipase (Novo 435).

Fe3O4 Nanoparticle-Polyacrylonitrile Composite Magnetic Beads Decorated with Candida antarctica Lipase B for Long-Term Reusability in the Hydrolysis of Esters

“…In our previous work, we fabricated magnetic PAN composite beads with rich nanosized pores (specific surface area of 23 m 2 ·g –1 , pore volume of 0.13 cm 3 ·g –1 , and average pore size of 22 nm), good magnetism (paramagnetism of 9.9 emu·g –1 ), good thermal and chemical stabilities, and good mechanical strength. These beads were used to physically immobilize CALB with favorable performance through one-step phase inversion . However, we observed that if the immobilized CALB was washed with 50% EtOH after the 10th cycle, then their activity increased by over 20% in the 11th cycle.…”

An efficient and sustainable Pd‐nanomagnetic heterogeneous catalyst for the reduction of nitroarene and environmental pollutant

“…Silica-coated magnetic Fe 3 O 4 was prepared from the previous method. 63 The Fe 3 O 4 @SiO 2 (0.5 g) was mixed into 50 mL of toluene using ultrasonic agitation, followed by dropwise addition of APTMS (2.86 mmol) while vigorously stirred and refluxed for 24 h. After being functionalized with amine groups, the APTMS/MNP residue was extracted using an external magnet, rinsed thrice with 20 mL of toluene, and dried for 12 h at 80 C. The presence of an amino group was confirmed using the ninhydrin test. A small amount of the compound was treated with a 5% ninhydrin solution in a water bath.…”

d-Amino Acid Oxidase Immobilized on Pt Nanoparticle-Loaded Porous SiO2 Nanospheres Coated with a Zirconium-Based Coordination Polymer for Catalytic Deamination of d-Alanine

“…1 Silica (SiO 2 )-based materials have been extensively investigated for immobilization of enzymes. 2,3 The enzyme immobilizations can be categorized into three types, encapsulation using SiO 2 capsules, 4,5 core SiO 2 nanoparticles coated with functional materials for enzyme immobilization, 6−8 and enzymes embedded in nano-and microporous SiO 2 . 9,10 Using metal−organic framework ZIF-8 nanoparticles as templates, glucose oxidase and horseradish peroxidase were coencapsulated by SiO 2 capsules.…”

“…4 Fe 3 O 4 nanoparticles coated with SiO 2 were used as templates for preparing hollow porous nanocomposites to immobilize lipase. 5 Silica microspheres were coated with polyethyleneimine (PEI) and polydopamine (PDA), and PDA/PEI-SiO 2 was used to immobilize carbonic anhydrase. 6 SiO 2 nanoparticles were coated with the functional peptide and can specifically immobilize SpyTag-fused enzymes xylanase and lichenase through covalent bonding.…”

“…Silica (SiO 2 )-based materials have been extensively investigated for immobilization of enzymes. , The enzyme immobilizations can be categorized into three types, encapsulation using SiO 2 capsules, , core SiO 2 nanoparticles coated with functional materials for enzyme immobilization, − and enzymes embedded in nano- and microporous SiO 2 . , Using metal–organic framework ZIF-8 nanoparticles as templates, glucose oxidase and horseradish peroxidase were coencapsulated by SiO 2 capsules . Fe 3 O 4 nanoparticles coated with SiO 2 were used as templates for preparing hollow porous nanocomposites to immobilize lipase . Silica microspheres were coated with polyethyleneimine (PEI) and polydopamine (PDA), and PDA/PEI-SiO 2 was used to immobilize carbonic anhydrase .…”