Applying Research On Gas-assisted Magnetic Separation For Scalable And Continuous Separation Of Proteins

Magnetic separation technology has been developed for many years, and mostly applied in the field of bioseparation and water treatment because of its various advantages,such as easy separation, and sample targeted. However, it still suffers from some limitations in large-scale separations and continuous problem, thus has not been widely applied in the industry. In this study, the technology that combined magnetic separation with flotation was used for the separation of proteins-loaded magnetic particles. It was called as gas-assisted magnetic separation(GAMS). Selecting MPNs with mean diameter of 3.3 μm for separation of BSA as a separation model, the whole process was carried out by intermittent, continuous and the whole continuous separation process research. The main results are as follows:1) The magnetic poly(glycidyl methacrylate) microspheres(GMA) were first prepared by dispersion polymerization method, followed by the ring-opening reaction of epoxy groups with EDA. Once generated, the microspheres were applied for separation of protein through electrostatic attraction. The effects of initial BSA concentration, medium pH and ionic strength on BSA adsorption capacity were studied and the maximum adsorption capacity was achieved at pH7.2.2) The effects of main process parameters on separation performance of interval gas-assisted magnetic separation in extraction, washing and back-extration process were investigated to obtain the optimal parameters. Then the effects of pH, gas flow rate, loading volume were investigated, and the main conclusions for these studies were as follows: For solution with MPNs concentration of 0.72 mg/m L, pH of 7.2, loading volume of 250 m L, the separation rate was 410 m L/min and recovery was 98% at gas flow rate of 60 mL/min. The results showed that bubbles could greatly improve separation rate of magnetic separation process and remotely capture magnetic particles. Compared with magnetic separation, gas-assisted magnetic separation had less dependence on high magnetic field, and easier scale-up of process. Meanwhile, no proteins were desorbed from magnetic particles and no changes of protein conformation were detected after flotation.3) Next, the continuous GAMS equipment was further studied, the throughput of GAMS for continuous separation of extraction was 24 L/h at gas flow rate of 250 mL/min. Furthermore, magnetic particles of more than 95% were recovered from magnetic roller on the top and less than 0.0389 mg/m L flowed out from clear solution at the bottom outlet, showing that the whole process complied with the conservation of mass. It was proved that this separation scale was achieved for continuous separation of magnetic particles from bioseparation solution.4) Based on the research of the unit processes, the pilot equipment of continuous gas-assisted magnetic separation would run successfully for extraction, washing and back-extration process of proteins. Meanwhile, the continuous operation process was achieved and proved its validity in separation of magnetic materials.