Extracellular Biosynthesis of Silver Nanoparticles using Bacterial Isolate from Saline Soil

Abstract

Nanotechnology is now known to be an area related to research and technology development. Nanoparticles have potential applications in the field of electronics, medicine and health. Nanotechnology is also proved in the medical field including therapeutics, drug discovery and diagnosis of diseases. An attempt has been made to isolate and identify the bacteria from saline soil and screening of all these bacteria for the synthesis of silver nanoparticles. Different bacterial cultures were isolated from saline soil samples from Baramati region. Isolated cultures were screened for extracellular biosynthesis of silver nanoparticles. The color change (white to brown) was observed after 72 hours of incubation. Among those bacteria the bacterial culture which showed absorption peaks in the range of 420-430 nm was selected for further characterization. Selected culture was identified using phenotypic and genotypic characteristics and was found to be Bacillus cereus. Characterization of nanoparticles was done using UV-visible spectral analysis, FTIR, SEM and XRD. The preparation showed characteristic absorption peak at 433 nm. SEM analysis illustrated that the silver nanoparticles formed were fairly uniform in size with a hexagonal shape and an average diameter of 94 nm. FTIR spectra revealed the presence of amino-methyl stretching groups and carbonyl groups. The antibacterial activity of the synthesized AgNPs was observed against human pathogens. The studies have indicated the potential of bacterial synthesized silver nanoparticles as bactericidal against human pathogens.