Bacteria-mediated synthesis of Mg–Fe2O3 nanocomposite and its antibacterial and antibiofilm activities

Biogenic synthesis is one of the simplest methods to synthesize Magnesium-iron oxide nanoparticles using Brevibacterium brevis isolated from green onion (Allium fistulosum) sample extract, and to check their effectiveness against pathogenic bacteria and to check their ability in various biological activities. Biogenic synthesis methods are eco-friendly, non-toxic, inexpensive, stable, and widely used in many applications. This study reports a bacteria-mediated synthesis of Mg–Fe 2 O 3 nanocomposites and evaluates their antibacterial and antibiofilm activities, highlighting the potential of plant-associated microorganisms as biofactories for functional nanomaterials. The magnesium-iron oxide nanoparticles were characterized and validated using ultraviolet-visible (UV-Vis) spectroscopy, X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FTIR). The biosynthesized nanoparticles showed distinct absorption peaks at 273 - 328 nm for UV-Visible spectra. Also, the crystalline structure confirms the synthesis of the Mg–Fe 2 O 3 nanocomposite. The FTIR spectra showed the composite peak to be between 500 cm −1 and 4000 cm −1 , the vibrational peaks of MgO at 3429.24 cm −1 and Fe 2 O 3 at 881.81 cm −1 . The synthesized magnesium-iron oxide nanoparticles were also assessed for various biological activities, such as antibacterial activity, antioxidant activity, anti-inflammatory activity, antibiofilm inhibition, and Minimum Inhibitory Concentration (MIC), exhibiting significant results. Simultaneously, the nanoparticles were very effective against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, and Escherichia coli, which have been shown through SEM and FTIR analysis of the cell interaction of each organism. The Mg–Fe 2 O 3 nanoparticles can damage the cell walls and an affects the morphology of pathogenic microorganisms, which is explained by the high antibacterial activity of these MgO/Fe 2 O 3 nanoparticles.