A rapid one-step process for the isolation of antibacterial peptides by silica-decorated Fe3O4nanoparticles

Antimicrobial peptides (AMPs), which are widely used as food preservatives, were purified to control the spoilage microorganism Alicyclobacillus acidoterrestris. The AMPs were produced by Pediococcus acidilactici CICC10344 and purified by silica-decorated Fe3O4 nanoparticles (SMNPs). The SMNPs were synthesized and characterized by transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR). The diameter of the SMNPs was 31 ± 7 nm. The VSM measurements indicated that the saturation magnetization value (Ms) of the SMNPs was 30 emu/g. We monitored AMP binding to the surface of Fe3O4 nanoparticles by FT-IR, showing that the amide had been successfully formed. The optimal condition for purification by SMNPs was an AMP concentration of 0.5 mg/mL for 30 min of exposure. The AMP purified by SMNPs retained good antimicrobial activity in pH 4–8 and temperature of 80 °C and 100 °C for 20 min. Scanning electron microscope (SEM) images indicated that a likely antibacterial mechanism is pore formation in the cell membrane. The one-step process proposed in the present work is convenient and effective for the purification of antibacterial peptides that may be widely used for the purification of other peptides.