Green Synthesis of Zinc Oxide Nanoparticles from Lyngbya sp. and Their Antibacterial Activity

In this study, the antibacterial activity of zinc oxide (ZNo NPs) was evaluated. ZnO NPs are considered as one of the many multifunctional inorganic nanoparticles with potent antibacterial properties. ZnO NPs were synthesized from the Lyngbya sp. extract.Following the green synthesis method,several other methods were used to characterize the biologically produced ZnO nanoparticles, including X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), atomic force microscopy (AFM), and UV–visible spectrophotometry (UV-Vis).The AFM results showed 52.09 nm diameter as an averagesize of ZnO NPs, while the shapes of NPs were irregular as revealed through the FE-SEM image.Also, using UV-visible a cut-off phenomenon of the biological synthesized ZnO was found to be around 265 nm. The antibacterial activity of ZnO NPs at 0.05, 0.025, 0.0125, 0.0062, 0.0031 and 0.0015 gm/mlconcentrations were also tested on both Escherichia coli (Gram-negative bacteria) and Staphylococcus aureus (Gram-positive bacteria). The results demonstrated the inhibitory effects of ZnO NPs on S. aureus at0.05,0.025,0.0125, and 0.0062 gm /ml with inhibition zone of 10 ,9 ,8 and 6 mm respectively.While the E. coli results showed a growth inhibition at 0.05, 0.025, 0.0125 and 0.0062 gm/ml concentration treatments of ZnO NPs, represented by 22, 20, 18 and 10 mm of inhibition zone respectively.