Open AccessRole of catalytic protein and stabilising agents in the transformation of Ag ions to nanoparticles by Pseudomonas aeruginosa
Author(s) -
Ali Jafar,
Hameed Abdul,
Ahmed Safia,
Ali Muhammad Ishtiaq,
Zainab Shama,
Ali Naeem
Publication year - 2016
Publication title -
iet nanobiotechnology
Language(s) - English
Resource type - Journals
ISSN - 1751-875X
DOI - 10.1049/iet-nbt.2015.0093
Subject(s) - silver nanoparticle , transmission electron microscopy , silver nitrate , nanoparticle , chemistry , nuclear chemistry , metal , fourier transform infrared spectroscopy , reducing agent , metal ions in aqueous solution , extracellular polymeric substance , infrared spectroscopy , rhamnolipid , spectroscopy , ionic bonding , molecule , nanotechnology , pseudomonas aeruginosa , chemical engineering , ion , materials science , bacteria , organic chemistry , biofilm , engineering , genetics , physics , quantum mechanics , biology
Biological routes of synthesising metal nanoparticles (NPs) using microbes have been gaining much attention due to their low toxicity and eco‐friendly nature. Pseudomonas aeruginosa JP2 isolated from metal contaminated soil was evaluated towards extracellular synthesis of silver NPs (AgNPs). Cell‐free extract (24 h) of the bacterial isolate was reacted with AgNO 3 for 24 h in order to fabricate AgNPs. Preliminary observations were recorded in terms of colour change of the reaction mixture from yellow to greyish black. UV‐visible spectroscopy of the reaction mixture has shown a progressive increase in optical densities that correspond to peaks near 430 nm, depicting reduction of ionic silver (Ag + ) to atomic silver (Ag 0 ) thereby synthesising NPs. X‐ray diffraction spectra exhibited the 2θ values to be 38.4577° confirming the crystalline and spherical nature of NPs [9.6 − 26.7 (Ave. = 17.2 nm)]. Transmission electron microscopy finally confirmed the size of the particles varying from 5 to 60 nm. Moreover, rhamnolipids and proteins were identified as stabilising molecules for the AgNPs through Fourier transform‐infrared spectroscopy. Characterisation of bacterial crude and purified protein fractions confirmed the involvement of nitrate reductase (molecular weight 66 kDa and specific activity = 3.8 U/mg) in the Synthesis of AgNPs.