Copper Oxide Nanoparticles: Synthesis from Citrus Fruits and Coconut Coir and their Antimicrobial Activity

Background: nanotechnology has been one of the most active research fields in present times. Methods: The copper oxide (CuO) nanoparticles (NP) were synthesised from aqueous extracts of coconut coir and citrus fruits (lemons, oranges, and tangerines). Results: The characterization of nanoparticles was done by UV/Vis and FT-IR spectroscopy. These were examined for their activity against E. coli (gram-negative) and Bacillus species (gram-positive). The highest activity was observed at a maximum dose of 200 mg/ml. In all four samples (different dilutions), both strains exhibited a moderate zone of inhibition compared to their respective controls. Also, the zone of inhibition increased with increasing CuO NP concentrations from 100mg/ml to 200mg/ml for both E. coli as well as Bacillus sp. In addition, while comparing citrus fruits, the zone of inhibition for tangerine CuO NPs was the highest in both bacterial species. However, in comparison with the nanoparticles synthesised using citrus fruits, the zone of inhibition obtained using coconut nanoparticles showed intermediate results against E. coli and Bacillus sp. Conclusion: The copper oxide nanoparticles obtained from the citrus fruits and coconut coir were found to have good antibacterial potential.