Int. J. Nanoparticles, Vol. 11, No. 3, 2019 239 Copyright © 2019 Inderscience Enterprises Ltd. Microwave assisted green synthesis of ZnO and Ag doped ZnO nanoparticles as antifungal and antibacterial agents using Colocasia esculenta leaf extract Kiran Kumar Prem Kumar Department of Chemistry, ATME College of Engineering, 13th Kilometer Mysore-Kanakapura Bangalore Road, Mysuru-570028, Karnataka State, India Email: kiran.pbs@gmail.com Nandipura D. Dinesh* Department of Chemistry, Adichunchanagiri Institute of Technology, Chikkamagaluru, Karnataka State, India Email: nddineshait@gmail.com *Corresponding author Satish Kumar Murari Department of Chemistry, P.E.S. College of Engineering, Mandya-571401, Karnataka State, India Email: murari_sk@hotmail.com Abstract: Considering the growing popularity of biosynthesis methods, the use of plant extracts for environment friendly synthesis of nanoparticles and the novel biomedical applications of zinc oxide (ZnO), the present study aims to synthesise ZnO and Ag doped ZnO nanoparticles through microwave assisted green synthesis method using the leaf extract of Colocasia esculenta. The nanoparticles synthesised were characterised for the assessment of their crystal structure, chemical phases, optical properties, distribution of particle size, stability, morphology, elemental composition, etc. by using a range of techniques, taking into account that the benefits of ZnO nanoparticles as piezoelectric conductors, transducers, antimicrobial agents, etc., predominantly depend on such morphological aspects. The efficiency of the synthesised nanoparticles as antimicrobial agents and comparison of the biocidal effects of doped and undoped nanoparticles were examined against the bacterial species, Bacillus subtilis and Escherichia coli, as well as the fungal species, Aspergillus oryzae and Saccharomyces cerevisiae, by using the cell culture technique. Keywords: ZnO nanoparticles; ZnO/Ag nanocomposites; nanotechnology; Colocasia esculenta; green synthesis; leaf extract; microwave method; characterisation; antifungal; antibacterial.