Green Synthesis of Zinc Oxide Nanoparticles Using Colocasia esculenta Tuber Peel Extract and Antimicrobial Studies of White Yam Pathogens

Aims: To biosynthesize and characterize Zinc Oxide NPs using Colocasia esculenta (Cocoyam) tuber peel extract as well as explores its antimicrobial potential against white yam pathogens.

Place and Duration of Study: Department of Chemistry, Benue State University, Makurdi, November, 2022.

Methodology: The method described by Nakade [1] was used for phytochemIcal analysis (Tanins, Saponins, Flavonoids, Alkaloids, Steriods, Quinones, Starch, Terpenoids and Glycosides).The biosynthesized ZnO NPs were characterized by UV-Visible, XRD, SEM, EDX and FTIR.

Antimicrobial sensitivity test was by the method described by Shiriki et al [2] with slight modification.

Results: Optimization studies revealed that the maximum rate of synthesis could be achieved with 0.50 M ZnO solution at 90 oC in 5 hours. The study revealed ZnO NPs that are crystalline with hexagonal shapes. The average crystallite size was 10 nm with a range of 7.81 nm- 9.23 nm. FTIR spectra of the tuber peel extract and the synthesized ZnO NPs revealed reducing, capping and stabilizing agents such as amines, peptides, amides and phenolic groups. The biosynthesized ZnO NPs exhibited antimicrobial action in a dose-dependent manner against five white yam pathogenic fungi: Aspergillus niger, Botryodioplodia theobromae, Zygosaccharomyces bailli, Zygosaccharomyces rouxil, and Myrothecium verrucaria as well as three bacteria: Klebsiella oxytoca, Serratia marcenscens, and Pseudomonas aeruginosa.

Conclusion: The biosynthesized ZnO NPs exhibited slightly to moderate and effective inhibition ranging from 15.54%- 98.52% on the test organisms when compared with standard antifungal (Fluconazole) and antibacterial (Ciprofloxacin) agents.