Green Synthesis of Silver Nanoparticles Using Chromobacterium violaceum: Characterization and Enhanced Antimicrobial Activity against Foodborne Pathogens

Abstract

This study presents the biosynthesis and characterization of nanoparticles assisted by Chromobacterium violaceum, and focuses on their role in antimicrobial activities. The isolation and identification of the organism were conducted using standard biochemical assays, while the characterization of the synthesized nanoparticles was performed using Brunauer–Emmett–Teller (BET) analysis, Fourier Transform Infrared (FTIR) analysis, and Xray diffraction (XRD). Production of AgNP was confirmed by surface plasmon resonance at 420 nm, peaking on day 4, and was optimal at pH 7. The biochemical assays revealed that the isolated organism is oxidase- and catalase-positive, but unable to ferment lactose or sucrose. BET analysis showed a high specific surface area (222.834 m²/g) and mesoporosity. FTIR spectra identified various functional groups such as hydroxyls, amides, and aromatics. XRD analysis revealed the crystalline face-centered cubic (FCC) structure of pure AgNPs, with characteristic peaks corresponding to (111), (200), (220), and (311) planes. The antimicrobial analysis demonstrated dose-dependent inhibition of Bacillus cereus and Aspergillus flavus, with variation in susceptibility among other isolates. The irregular responses of Staphylococcus aureus and Aspergillus niger at higher doses suggest complex interactions due to aggregation or microbial resistance mechanisms. Conclusively, C. violaceum-synthesized AgNPs exhibit promising bioactivity, structural integrity, and surface characteristics for future applications.