title: Analysis of antimicrobial silver nanoparticles synthesized by coastal strains of Escherichia coli and Aspergillus niger.
abstract: The present study investigated the extracellular biosynthesis of antimicrobial silver nanoparticles by Escherichia coli AUCAS 112 and Aspergillus niger AUCAS 237 derived from coastal mangrove sediment of southeast India. Both microbial species were able to produce silver nanoparticles, as confirmed by X-ray diffraction spectrum. The nanoparticles synthesized were mostly spherical, ranging in size from 5 to 20 nm for E. coli and from 5 to 35 nm for A. niger, as evident by transmission electron microscopy. Fourier transform spectroscopy revealed prominent peaks corresponding to amides I and II, indicating the presence of a protein for stabilizing the nanoparticles. Electrophoretic analysis revealed the presence of a prominent protein band with a molecular mass of 45 kDa for E. coli and 70 kDa for A. niger. The silver nanoparticles inhibited certain clinical pathogens, with antibacterial activity being more distinct than antifungal activity. The antimicrobial activity of E. coli was more pronounced than that of A. niger and was enhanced with the addition of polyvinyl alcohol as a stabilizing agent. This work highlighted the possibility of using microbes of coastal origin for synthesis of antimicrobial silver nanoparticles.
authors.affiliation: Centre of advanced study in Marine Biology, Annamalai University, Parangipettai, 608502 Tamil Nadu, India. kathirsum@rediffmail.com
authors.forename: Kandasamy
authors.initials: K
authors.lastname: Kathiresan
authors.forename: Nabeel M
authors.initials: NM
authors.lastname: Alikunhi
authors.forename: SriMahibala
authors.initials: S
authors.lastname: Pathmanaban
authors.forename: Asmathunisha
authors.initials: A
authors.lastname: Nabikhan
authors.forename: Saravanakumar
authors.initials: S
authors.lastname: Kandasamy
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D000935:Antifungal Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D001234:Aspergillus niger / Q000378:metabolism*; D001419:Bacteria / Q000187:drug effects*; D004926:Escherichia coli / Q000378:metabolism*; D005658:Fungi / Q000187:drug effects*; D053768:Metal Nanoparticles / Q000032:analysis* / Q000648:ultrastructure; D008826:Microbial Sensitivity Tests; D046529:Microscopy, Electron, Transmission; D011142:Polyvinyl Alcohol / Q000737:chemistry; D012834:Silver / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D012835:Silver Nitrate / Q000378:metabolism; D014961:X-Ray Diffraction
chemical_list: D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D012834:Silver; D011142:Polyvinyl Alcohol; D012835:Silver Nitrate