title: Silver nanoparticles tolerant bacteria from sewage environment.
abstract: Silver nanoparticle (SNP) is a threat to soil, water and human health. Protection of environment from silver nanoparticles is a major concern. A sewage isolate, Bacillus pumilus treated with SNPs showed similar growth kinetics to that without nanoparticles. A reduction in the amount of exopolysaccharides was observed after SNPs--B. pumilus culture supernatant interaction. The Fourier transform infrared spectroscopy (FT-IR) peaks for the exopolysaccharides extracted from the bacterial culture supernatant and the interacted SNPs were almost similar. The exopolysaccharide capping of the SNPs was confirmed by UV-Visible, FT-IR and X-ray diffraction analysis. The study of bacterial exopolysaccharides capped SNPs with E. coli, S. aureus and M. luteus showed less toxicity compared to uncoated SNPs. Our studies suggested that the capping of nanoparticles by bacterially produced exopolysaccharides serve as the probable mechanism of tolerance.
authors.affiliation: Nanobio-Medicine Laboratory, School of Bio-Sciences and Technology, VIT University, Vellore 632014, India. sudheerkhan@vit.ac.in
authors.forename: Sudheer
authors.initials: S
authors.lastname: Khan
authors.forename: Amitava
authors.initials: A
authors.lastname: Mukherjee
authors.forename: Natarajan
authors.initials: N
authors.lastname: Chandrasekaran
mesh_terms: D001419:Bacteria / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification; D001483:Base Sequence; D017931:DNA Primers; D053768:Metal Nanoparticles; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D011134:Polysaccharides / Q000633:toxicity; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012722:Sewage / Q000382:microbiology*; D012834:Silver / Q000633:toxicity*; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D017931:DNA Primers; D011134:Polysaccharides; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D012834:Silver