Abstract : Cyanobacteria are procaryotic microorganisms distributed in aquatic environment that involved in the atmospheric nitrogen fixation. Such organisms have an ability to synthesize nano particles in an aqueous culture medium. The current study isolated the Oscillatoria cortiana from the paddy field soil and mass cultured under microbiology culture lab. The aqueous extract of O. cortiana synthesized silver nano particles and was confirmed by UV-Visible Spectrophotometer (showed peak at nearly 230nm and 430 nm), FTIR (peaks indicated the presence of functional groups: -C-O-C, N=O, C=O and -OH groups), SEM-EDX analysis (particle size ranged from17.79 to 19.32 nm). Synthesized O-AgNPs was tested against entero bacterial pathogens showed inhibition zone ranged from 1.4 ±0.1 to 1.8±0.2 cm for E.coli and 1.4±0.2 to 2.1±0.1cm for Bacillus cultures.This green synthesis technology of nano particle synthesis from Oscillatoria cortiana could be suggested for application in medicine, pharmaceutical field and bioremediation.

Keyword : Cyanobacteria, Oscillatoria, Nano particles and antibacterial activity.