Green synthesis of silver nanoparticles using Mung bean and the probiotic Bacillus clausii and their evaluation as single or synergistic antibacterial agents

Abstract

Biological green synthesis of silver nanoparticles (AgNPs) offers potent antimicrobial properties and provides a promising approach against drug-resistant microbes. The present study aims to synthesize AgNPs using Mung bean (Vigna radiate) aqueous extract and the probiotic Bacillus clausii, and to evaluate their antibacterial activity individually and in combination against several bacterial strains. Synthesized AgNPs were characterized by ultraviolet-visible spectroscopy (UV-vis) and scanning electron microscopy (SEM). V. radiata AgNPs were revealed at 450 nm, with spherical to oval shapes ranging in size from 15.9 to 23.0 nm; probiotic AgNPs were observed at 425 nm, also with a spherical shape ranging in size from 16.4 to 23.7 nm. The antibacterial assay was performed using the agar well diffusion method against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, and Escherichia coli. Results indicated that V. radiata aqueous extract and the probiotic solution did not exhibit any effect, whereas synthesized V. radiata and probiotic AgNPs showed antibacterial activity against all tested bacteria. AgNPs possessed higher antibacterial activity than individual AgNPs when used in combination against almost all bacteria studied. Therefore, it is suggested that using natural antimicrobial agents to synthesize NPs could serve as an eco-friendly alternative to antibiotics.

Keywords: Antimicrobial resistance; Enterogermina probiotics Bacillus clausii; Vigna radiata; antibacterial activity; antimicrobial agents; silver nanoparticles.