MAYANK RAJ, VIKAS KUMAR, CHARU BANSAL, AKASH SHARMA, VIVEK RAWAT, ZEENAT MADAN, SUSHIL KUMAR UPADHYAY, RAJ SINGH, DEEPAK YADAV AND MANOJ SINGH*
Department of Bio-Sciences and Technology, MMEC, Maharishi Markandeshwar (Deemed to be University),
Mullana, Ambala-133 207 (Haryana), India
*(e-mail: manoj.singh@mmumullana.org; Mobile: 87070 11151)
(Received: January 2, 2026; Accepted: February 8, 2026)
ABSTRACT
Orange (Citrus sinensis) is a common fruit crop widely distributed worldwide with the peel of its fruits representing about 50% of fruit mass. In the current study, orange peel was employed to mediate the synthesis of zinc oxide nanoparticles (ZnO-NPs) in a low-cost green approach. This study involved the synthesis of zinc oxide nanoparticles (ZnO-NPs) through an environmentally friendly method, utilizing orange fruit peel aqueous extract both as a stabilizer and a biological reducing agent, utilizing zinc nitrate hexahydrate as the zinc precursor. This approach minimized the reliance on large quantities of chemicals and removal of hazardous substances from the fabrication process, enhancing the antibacterial properties of the nanoparticles. In UV-visible spectroscopy, a typical Zn2+ surface plasmon resonance band was found at 338 nm, confirming the formation of ZnO-NPs. HR-TEM confirmed that the particles were homogenous and spherical, ranging between 40 to 100 nm. The Fourier-Transform Infrared (FTIR) spectra revealed information about the extract’s functional groups, which helped instabilizing ZnO-NPs. The strong and wide peak at 2359/cm was observed in the plant extract. The participation of the hydroxyl group (-OH) present in the extract’s compounds reduced of zinc ions. The antimicrobial efficacy of the synthesized ZnO nanoparticles was assessed against gram positive and negative bacteria, S. aureus, E. coli and P. aeruginosa, B. subtilis, utilizing the well diffusion method on media favourable for bacterial proliferation. The synthesized nanoparticles demonstrated significant bactericidal properties, successfully suppressing bacterial proliferation and creating noticeable zones of inhibition.
Key words: Antibacterial activity, characterization, green synthesis, ZnO-NPs, zone of inhibition