Biosynthesis of Zinc Oxide Nanoparticles from Orange Peel Extract and their Antimicrobial Activity

Abstract

The biosynthesis of zinc oxide nanoparticles (ZnO NPs) via an aqueous peel extract of Citrus sinensis represents a green and sustainable alternative to conventional synthesis methods, eliminating the need for toxic chemicals and diminishing energy consumption. Bioactive compounds present in the extract, such as flavonoids and polyphenols, serve as natural reducing and stabilizing agents during the nanoparticle formation process. Characterization via UV–VIS spectrophotometry confirmed the formation of crystalline and stable ZnO NPs. In this study, an aqueous orange-peel extract was employed as the biological reducing agent for the synthesis of ZnO nanoparticles from zinc nitrate as the precursor, and the influence of the precursor/extract ratio on the properties of the obtained particles was investigated. The antimicrobial activity of the synthesized ZnO NPs was tested against Escherichia coli and Staphylococcus aureus, with significant growth inhibition observed/particularly in the case of E. coli. The results obtained underscore the potential application of biosynthesized ZnO NPs in medicine, food preservation, and biodegradable packaging. This study confirms an efficient, eco-friendly and straightforward approach to the green synthesis of ZnO nanoparticles using orange peel extract.