Abstract

• This research deals with biosynthesis of zinc oxide nanoparticles using Calotropis giganteaL. (ma-yo-gyi), characterization and antimicrobial activities. The aim of this research is to synthesize, characterize and study the antimicrobial activities of biosynthesized zinc oxide nanoparticles. Leaves of Calotropis gigantea L. (Ma-yo-gyi) were collected from Kathitkan village in Aung Lan Township, Magway Region and identified in Department of Botany, Pyay University. The phytochemical screening of aqueous leaves extract of Calotropis gigantea L. was carried out by test tube method and aqueous leaves extract was also characterized by FT IR technique. Zinc oxide nanoparticles were biosynthesized fromzinc nitrate by method Iand method II using aqueous leaves extract of Calotropis gigantea L. as a reducing agent. Thermal stability of green synthesized zinc oxide nanoparticles by method I was studied by Thermogravimetric-Differential Thermal Analyzer (TG-DTA). The effects of calcination temperature on crystallize sizes of biosynthesized ZnO nanoparticles by method I was also studied. The crystallinity and purity of biosynthesized zinc oxide nanoparticles by methods I and II werestudied by X-ray Diffraction (XRD) technique. The biosynthesized ZnO nanoparticles by both methods were found to be crystalline in nature and which has hexagonal structure. The average crystallize sizes were calculated by using Debye-Scherrer equation and found to be in the range of (25-33) nm. The antimicrobial activities of biosynthesized ZnO nanoparticles on six microorganisms such as B. subtilis, B. pumilus, C. albicans, S. aureus, E. coli and P. aeruginosa were studied by ager well diffusion method. It was found that the high antimicrobial activities of biosynthesized ZnO NPs (23-26 mm) on gram positive and negative bacteria strain except P. Aeruginosa and also high activity on fungus like Candida albicans. For the investigation of the storage time of guava and tomato fruits at room temperature, biosynthesized ZnO nanoparticles coated on surface of these fruits and found to be fresh without any moltuntilone month