Synthesis and characterization of Zinc Oxide nanoparticles using marine Streptomyces sp. with its investigations on anticancer and antibacterial activity

Synthesis of zinc oxide nanoparticles (ZnONPs) by an ecological approach using Streptomyces sp. as reducing agent is reported. ZnONPs were synthesized from aqueous zinc chloride solution by cell-free supernatant of a novel isolate. Hyperchromic shift was observed at 364 nm using UV–visible spectroscopy and also by the naked eye as a color change from dark green to milk white. Evidence for proteins acting as reducing and capping agent was obtained by Fourier-transform infrared spectroscopy. From the X-Ray diffraction studies, the lattice planes and obtained peak positions confirmed the hexagonal close-packed crystalline structure of ZnONPs. Surface topographical studies revealed that the biosynthesized ZnONPs had spherical shape with mean diameter of about 20–50 nm. Transmission electron microscopy revealed that the nanoparticles had spherical structure with uniform distribution along the surface. The anticancer activity of the synthesized nanoparticles was evaluated against A549 lung cancer cells, and their antibacterial activity against Escherichia coli and Bacillus subtilis was analyzed and reported.