Multifunctional Silver Nanoparticles Synthesized via Exiguobacterium aurantiacum: Applications in Dye Remediation, Anticancer and Antibacterial Activity.

The study investigates adaptations of photovoltaic solar panel isolates and their applications. Exiguobacterium aurantiacum (KKOHNGU1) was extracted from a PV solar panel in Patan, Gujarat, India. The objective was to synthesize and characterize silver nanoparticles (AgNPs) using E. aurantiacum (KKOHNGU1) to evaluate their potential in environmental remediation, anticancer, and antibacterial activities. MALDI-TOF analysis identified secondary metabolites as stabilizing and reducing agents. AgNPs were characterized using UV-visible spectroscopy (peak at 425 nm), X-ray diffraction (peaks at 27.6°, 32.12°, and 46.06°), Fourier transform infrared spectroscopy field emission scanning electron microscopy and energy-dispersive spectroscopy, shows spherical crystalline AgNPs with a mean size (121.44 nm). AgNPs (15 mg/mL) showed antibacterial activities, especially against S. aureus, with a 17.5 mm zone of inhibition MIC (2-32 µg/mL), and MBC (32-150 µg/mL). The MTT assay revealed anticancer activity of AgNPs on the MDA-MB-231 breast cancer cell line with an IC₅₀ value of 172.96 µg/mL. A comparative study showed both bacteria and AgNPs had high potential for MB dye removal, with bacteria achieving 73.55% removal within 120 h and AgNPs showing 97.54% removal within 10 min. These results indicate E. aurantiacum and AgNPs have potential for environmental remediation, particularly in wastewater treatment.