Production of Silver Nanoparticles using Bacillus licheniformis Biofilm by Rotating Biological Contactor and their Antibacterial Activity

Nanoparticles show unique and considerably changed chemical, physical, and biological properties compared to bulk of the same chemical composition, due to their high surface-to-volume ratio. Biological synthesis of silver nanoparticles using microorganisms has received profound interest because of their potential to synthesize nanoparticles of various size, shape and morphology . Isolates were collected from the different area of agriculture soils of Kerman. For the identification and characterization of the culture, done morphological (colony color, shape and size) and biochemical tests. Cultures supernatants and bacterial wet biomass were mixed with AgNo3. Then the mixtures were kept on a rotating shaker at room temperature for a period of 24-48 h under dark and visible light illumination. Rotating biological contactor were used for biosynthesis of silver nanoparticles (AgNPs). Synthesis of AgNPs was initially observed by color change from greenish yellow to brown and were characterized by UV-Vis spectroscopy. The particle of silver nanoparticles was studied by Transmission Electron Microscopy (TEM). The antimicrobial activity of the AgNPs was investigated using Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus, by applying well diffusion method. UV-vis spectrum of the aqueous medium containing silver ion showed a peak at 420 nm corresponding to the plasmon absorbance of AgNPs. TEM micrograph showed formation of the AgNPs in the range of 2 nm−100 nm and the morphology of them is spherical. The silver nanoparticles exhibited higher antibacterial activity against Gram positive than Gram-negative bacteria. The synthesized AgNPs was produced by Bacillus licheniformis have a great biomedical application and represent a future for more therapeutic and pharmacological applications.