GREEN SYNTHESIS, XRD CHARACTERISATION AND ANTIBACTERIAL ACTIVITY OF ZINC OXIDE NANOPARTICLES

ABSTRACT

The avocado seed is a non edible part of the fruit that is normally discarded as waste, the avocado waste (seed) has a range of useful chemicals and is one source of phytochemicals. The Phytochemicals screening of avocado seed aqueous extract was done under controlled experiment. The result shows that flavonoids, saponins, terpenoids, eugenols, tannins, phenolics, glycosides, and alkaloids were present while steroids is absent. Zinc oxide nanoparticles (ZnO NPs) were synthesised from avocado seed aqueous extract using an environment- friendly synthesis approach.This research began with extracting avocado seed powder with distilled water. Then the avocado seed extract was mixed with zinc acetate dihydrate, and heated in a water bath at 70 °C, the mixture was stirred while NaOH was added until the mixture reached a pH of 12. The biosynthesised NPs were characterised using X-ray diffraction (XRD), which confirmed their crystalline nature.The XRD analysis data showed average crystallite size of 29.876 nm for the ZnO NPs. These ZnO NPs were then used as antibacterial agents against Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa). The result showed that ZnO NPs extracted from avocado seed has inhibition of 20 mm against S . aureus, therefore indicating the antibacterial activity of ZnO nanoparticles.