Next generation bioactive applications of Bacillus flexus by synthesized silver nanoparticles : A detailed investigation

Silver nanoparticles (AgNPs) synthesized through biological methods have emerged as a difficult alternative to traditional chemical synthesis due to their increased biocompatibility and environmental attainability. In this study, we investigated the stability and various biological activities of AgNPs synthesized using Bacillus flexus B-AgNPs. The solidification of the nanoparticles was monitored for one month using UV-Vis spectroscopy, which revealed consistent surface plasmon resonance (SPR) peaks around 430-450 nm, indicating sustained nanoparticle integrity. The synthesized B-AgNPs proved significant antifungal, antibacterial, and antioxidant activities. The antifungal efficacy was evaluated against multiple strains of Alternaria solani with B-AgNPs showing superior inhibition compared to standard antifungal drugs. Even at low concentrations, the nanoparticles demonstrated powerful inhibitory effects on Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Results indicate that B-AgNPs exhibit antioxidant activity also approximate to that of DPPH, particularly at higher concentrations (50 ppm), where the scavenging activity of B-AgNPs is nearly the same as that of DPPH. These findings indicate that B-AgNPs synthesized using B. flexus possess important potential uses in agriculture and biomedicine, with superior stability and biological activity compared to conventional methods.