title: Controlled biosynthesis of silver nanoparticles using nitrate reductase enzyme induction of filamentous fungus and their antibacterial evaluation.
abstract: The controlled synthesis of silver nanoparticles (AgNPs) using cell-free filtrate of Fusarium oxysporum fungus was investigated. The effect of fungal incubation period on nanoparticle formation and nitrate reductase enzyme activity was studied using UV-visible spectroscopy and Harley assay, respectively. The highest AgNP formation was observed in the cell-free filtrate of biomass harvested at the early stationary phase where the NR enzyme activity is the maximum. Mixing of the cell-free filtrates of fungal cultures obtained at 23, 28, and 33 °C with silver nitrate solution confirms the higher productivity of AgNP biosynthesis using the cell-free filtrate of fungus incubated at 28 °C. The effect of some factors such as carbon and nitrate sources and light in fungal incubation period on nitrate reductase induction and AgNP formation was also evaluated. In conclusion, increasing nitrate and carbon sources and presence of light induced NR enzyme and produced AgNPs with smaller size, higher monodispersity, and productivity. Results revealed that the presence of ammonium prevents the NR enzyme secretion and causes to the lower productivity of AgNPs.
authors.affiliation: a Department of Cellulose and Paper Technology, Faculty of New Technologies and Energy Engineering , Shahid Beheshti University , Zirab Campus , Tehran , Iran.
authors.forename: Sepideh
authors.initials: S
authors.lastname: Hamedi
authors.affiliation: b Nanomaterials Group, Department of Materials, Engineering Faculty , Tarbiat Modares University , Tehran , Iran.
authors.forename: Masumeh
authors.initials: M
authors.lastname: Ghaseminezhad
authors.affiliation: c Department of Chemical Technologies , Iranian Research Organization for Science and Technology (IROST) , Tehran , Iran.
authors.forename: Soheila
authors.initials: S
authors.lastname: Shokrollahzadeh
authors.affiliation: d Department of Biotechnology, Faculty of chemical engineering , Tarbiat Modares University , Tehran , Iran.
authors.forename: Seyed Abbas
authors.initials: SA
authors.lastname: Shojaosadati
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D002244:Carbon / Q000494:pharmacology; D004790:Enzyme Induction / Q000187:drug effects / Q000528:radiation effects; D005670:Fusarium / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism* / Q000528:radiation effects; D008027:Light; D053768:Metal Nanoparticles / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D050901:Nitrate Reductase / Q000096:biosynthesis*; D012834:Silver / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D013696:Temperature
chemical_list: D000900:Anti-Bacterial Agents; D012834:Silver; D002244:Carbon; D050901:Nitrate Reductase
keywords: Fusarium oxysporum; Nitrate reductase enzyme induction; antibacterial activity; green synthesis; silver nanoparticles