Agro-Waste-Mediated Green Synthesis of Silver Nanoparticles from Harum Manis and Sala Mango Peel Waste and Their Antimicrobial Activity

Abstract

Green synthesis of silver nanoparticles (AgNPs) is increasingly recognised as an environmentally sustainable alternative to traditional physicochemical synthesis methods. The growing challenge of antimicrobial resistance has further intensified the search for effective and sustainable antimicrobial materials. In this study, mango peel agro-waste from the Harum Manis and Sala varieties was utilised as a natural reducing and stabilising agent for the biosynthesis of AgNPs.The formation of AgNPs was demonstrated using UV–Visible spectroscopy, which showed characteristic surface plasmon resonance peaks within the range of 400–500 nm. Fourier Transform Infrared (FTIR) analysis revealed the presence of functional groups associated with biomolecules responsible for nanoparticle reduction and stabilisation. The antimicrobial activity of the synthesised AgNPs was assessed against Escherichia coli and Staphylococcus aureus using disc diffusion and minimum inhibitory concentration (MIC) assays. Both mango peel-derived AgNPs exhibited moderate antibacterial activity with inhibition zones ranging from 8–10 mm, while the MIC value for both bacterial strains was determined to be 0.1 g/mL. These findings demonstrate the potential of mango peel agro-waste as a renewable resource for AgNP synthesis and highlight its promising application as an eco-friendly antimicrobial agent.