Biosynthesis of Silver Nanoparticles Using Fungus Penicilliumbrevicompactum Isolated from Plump and Zinc Mine in Zanjan

In biological methods، microorganisms such as bacteria، fungi، actinomycets and yeasts are used to produce metal nanoparticles. Fungi are extremely good candidates in the synthesis of silver nanoparticles because of their ability to secrete large amounts of enzymes. The aim of this study was the biosynthesis of silver nanoparticles by Penicillium spp. isolated from the soil of plump and zinc mine in Zanjan city (Iran). After culturing، growth of colonies and isolation of Penicillium spp.، 15 g of the fungal biomass was mixed into 1 mM silver solution for 72 h incubation. The production of silver nanoparticles was characterized by UV-vis spectroscopy، X-ray diffraction (XRD) and transmission electron microscopy. Among the sixteen kinds of isolated fungi، six species were recognized as Penicillium of which just the fungus Penicilliumbrevicompactum was found to be able to produce silver nanoparticles. The production of silver nanoparticles was preliminarily approved by observing the color change of the reaction solution from colorless to yellowish brown. The synthesis of silver nanoparticles was confirmed by observing the characteristic peak at 406-425 nm. The presence of crystalline silver nanoparticles was confirmed by observing peaks in (111)، (200)، (220)، (311) in the XRD analysis. Transmission electron microscopy images showed that silver nanoparticles were produced in the size range of 50 -100 nm in spherical shape mainly extracellular at the surface of mycelium. The fungus was recognized to be Penicilliumbrevicompactumusing slide culture method، growth on Czapek yeast agar and Keratin-sucrose agar.