Comparative studies on biosynthesis, partial characterization of silver nanoparticles and antimicrobial activities in some edible mushroom

Microbial silver nanoparticles have been known to have bactericidal effects but the antimicrobial mechanism have not been clearly revealed. The use of microorganisms in the synthesis of nanoparticles emerges as an eco-​friendly approach. The biol. process with the ability to study the shape of particles produced would therefore be a lime light of modern nanotechnol. In the present study biosynthesis of silver nanoparticles using edible mushrooms Viz., Pleurotus florida and Pleurotus flabellatus, partial characterization of silver nanoparticle and its antimicrobial study have been reported. It was found that aq. silver ions of 5mM concn. were reduced to silver metal nanoparticles by nitrate dependent reductase and a shuttle quinone extracellular process when treated with fungal supernatant of Pleurotus florida, in 72h and Pleurotus flabellatus in 24h. Partial characterization of synthesized silver nanoparticles, investigated by UV-​VIS Spectroscopy showed increased productivity at 386nm with sharp and intense surface plasmon. It is found that silver nanoparticles are bound to protein through carboxylate group of aminoacid residues. The synthesized silver nanoparticle showed high bactericidal activity against Gram-​pos. (Staphylococcus aureus) and Gram-​neg. (Pseudomonas aeruginosa) bacteria. The mechanism of the Ag NP bactericidal activity is discussed in terms of Ag NP interaction with the cell membranes of bacteria