Investigation of benzaldehyde lyase (BAL, EC 4.1.2.38) immobilization and reactions on magnetic nanoparticles

Superparamagnetic silica-coated magnetite (Fe3O4) nanoparticles with immobilized metal affinity ligands were prepared for benzaldehyde lyase enzyme (BAL, EC 4.1.2.38) immobilization. First, magnetite nanoparticles were synthesized by co-precipitating Fe2+ and Fe3+ in an ammonia solution. Then silica was coated on the Fe3O4 nanoparticles using a sol?gel method to obtain magnetic silica nanoparticles. The condensation product of 3-Glycidoxypropyltrimethoxysilane (GPTMS) and iminodiacetic acid (IDA) was immobilized on them and after charged with Cu2+, the magnetic silica nanoparticles with immobilized Cu2+ were applied for the adsorption of BAL. X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR) methods were used to characterize the epoxy-functionalized Fe3O4@SiO2 core?shell magnetic nanoparticles. XRD (Scherer?s equation) and TEM results indicate that the primary particle size of magnetite was around 11 nm.According to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) results, these magnetic nanoparticles specifically captures 6XHis tagged BAL from crude extract of E.coli BL21(DE3)pLysS/BALHIS. This study shows that the silica-coated magnetite (Fe3O4) nanoparticles with immobilized metal affinity ligands are eligible for immobilized metal-ion affinity adsorption for histidine tagged recombinant proteins with its high capacity (40 mg/g) and selectivity.