BANANA PSEUDOSTEM-MEDIATED GREEN SYNTHESIS OF SILVER NANOPARTICLES: CHARACTERIZATION AND EVALUATION OF ANTIFUNGAL ACTIVITY

Abstract

The present study reports an eco-friendly, cost-efficient, rapid, and easy method for synthesization of silver nanoparticles (AgNPs) using banana pseudo-stem extract (BSE) as a reducing and capping agent. The formation of AgNPs was confirmed by changing their colour to dark brown due to the surface Plasmon resonance (SPR) phenomenon. The different factors affecting silver reduction were investigated. The optimal synthesis conditions for the AgNPs were determined by varying parameters such as the pH of the AgNO₃, the AgNO₃ concentration, the BSE concentration, the temperature, and the reaction time. The optimum conditions were AgNO₃ (2.0 mM), BSE (2%), pH (11), temperature (80ºC for 20 min), and incubation time (6 h). The UV-vis spectrum of AgNPs revealed a characteristic surface Plasmon resonance (SPR) peak at 404.5 nm. Silver nanoparticles were characterized. X-ray diffraction revealed their crystalline nature. The scanning electron microscope revealed near-spherical, monodisperse nanoparticles, with an average size of 50-92 nm. Fourier transform infrared spectroscopy affirmed the role of BSE as a reducing and capping agent of silver ions. The fungicidal activity of green-synthesized BSE-AgNPs at different concentrations (10, 50, 100, 150, 200 and 250 ppm) was tested against two soil-borne plant pathogens, viz., Sclerotium rolfsii Sacc and Pythium aphanidermatum (Edson) Fitzp. The result showed that BSE-AgNPs at 250 ppm concentration showed cent per cent inhibition against S. rolfsii, whereas BSE AgNPs at 300 ppm showed cent per cent inhibition against P. aphanidermatum.