Preparation of anionic polyelectrolyte modified magnetic nanoparticles for rapid and efficient separation of lysozyme from egg white

• PSS–MNPs were prepared by a two-step reaction.
• PSS–MNPs were found to enable effective separation of lysozyme from egg white.
• The maximum adsorption capacity of PSS–MNPs for lysozyme was 476.2 mg g−1.
• The separation process was fast and highly efficient.
• The separated lysozyme from egg white demonstrated high purity.

Poly(sodium 4-styrenesulfonate) modified magnetic nanoparticles (PSS–MNPs) were successfully synthesized and characterized by transmission electron microscopy, scanning electron microscopy, zeta potential, vibrating sample magnetometry, and Fourier-transform infrared spectrometry. The PSS–MNPs were found to enable effective separation of lysozyme from egg white. The impacts of solution pH, ionic strength, and contact time on the adsorption process were investigated. The adsorption kinetic data were well fitted using a pseudo-second-order kinetic model and the adsorption equilibrium can be reached in 3 min. The adsorption isotherm data could be well described by the Langmuir equation. The maximum adsorption capacity of PSS–MNPs for lysozyme was calculated to be 476.2 mg g−1 according to the Langmuir adsorption isotherm. The fast and efficient adsorption of lysozyme by PSS–MNPs was mainly based on electrostatic interactions between them. The adsorbed lysozyme can be eluted using 20 mM phosphate buffer (pH 7.0) containing 1.0 M NaCl with a recovery of 96%. The extracted lysozyme from egg white demonstrated high purity, retaining about 90.7% of total lysozyme activity.