Superparamagnetic Polymer Emulsion Particles from a Soap-Free Seeded Emulsion Polymerization and their Application for Lipase Immobilization

Abstract

Using emulsion copolymer of styrene (St), glycidyl methacrylate (GMA) and 2-hydroxyethyl methacrylate (HEMA) as seed latexes, the superparamagnetic polymer emulsion particles were prepared by seeded emulsion copolymerization of butyl methacrylate (BMA), vinyl acetate (VAc) and ethylene glycol dimethacrylate in the presence of the seed latexes and superparamagnetic Fe3O4/SiOx nanoparticles (or Fe3O4-APTS nanoparticles) through a two-step process, without addition of any emulsifier. The magnetic emulsion particles named P(St-GMA-HEMA)/P(BMA-VAc) were characterized by transmission electron microscope and vibrating sample magnetometry. The results showed that the magnetic emulsion particles held a structure with a thinner shell (around 100 nm) and a bigger cavity (around 200 nm), and possessed a certain level of magnetic response. The resulting magnetic emulsion particles were employed in the immobilization of lipase by two strategies to immobilized lipase onto the resulting magnetic composites directly (S-1) or using glutaraldehyde as a coupling agent (S-2), thus, experimental data showed that the thermal stability and reusability of immobilized lipase based on S-2 were higher than that of S-1.

P(GMA‐HEMA)/SiO2 Nanofilm Constructed Macroporous Monolith for Immobilization of Pseudomonas Fluorescens Lipase

“…Within around 600 min, the free PFL almost lost its activity, whereas the immobilized PFL still retained 58.0 % of its initial activity. This improvement in denaturation resistance of the immobilized lipase at higher temperature is ascribed to the formation of covalent bonds during the immobilization process, which enhanced the rigidity of the molecular structure of lipase . In addition, the support with macroporous network structure confined the lipase in its internal regions well, which could provide a suitable microenvironment to protect enzyme molecules against high temperature.…”

“…As shown in Figure a, after 15 consecutive cycles of reuse, PFL@P(GMA‐HEMA)/SiO 2 retained 80.0 % of its initial activity, whilst PFL@SiO 2 was only 15.5 % after 8 cycles. Candia Rugosa lipase immobilized onto functional polyphosphazene cyclomatrix microspheres retained nearly 50 % of its initial activity after 10 cycles of application . By covalent immobilization of Candida Antarctica Lipase B on an epoxy‐functionalized silica support, 88.3 % of its original activity was retained after consecutive 7 runs .…”