Biogenic silver nanoparticles associated with silver chloride nanoparticles (Ag@AgCl) produced by laccase from Trametes versicolor.

Nelson Durán,Olga Rubilar,Raphael Cuevas,Livia Cordi,Maria Cristina Diez

doi:10.1186/2193-1801-3-645

Abstract

In the present study, semi-purified laccase from Trametes versicolor was applied for the synthesis of silver nanoparticles, and the properties of the produced nanoparticles were characterized. All of the analyses of the spectra indicated silver nanoparticle formation. A complete characterization of the silver nanoparticles showed that a complex of silver nanoparticles and silver ions was produced, with the majority of the particles having a Ag2+ chemical structure. A hypothetical mechanistic scheme was proposed, suggesting that the main pathway that was used was the interaction of silver ions with the T1 site of laccase, producing silver nanoparticles with the concomitant inactivation of laccase activity and posterior complexing with silver ions.

Highlights

The literature has demonstrated that the mechanism used for the formation of metal nanoparticles is the action of a large number of enzymes secreted by fungi in special reductases (Ahmad et al 2003; Durán et al 2007; Durán et al 2011; Jain et al 2011)
The aim of this study was to evaluate the biosynthesis of silver nanoparticles through the semi-purification of laccase from Trametes versicolor, a white-rot fungus, as well as to characterize the nanoparticles by electronic microscopy, analysis of the distribution of size by dynamic light scattering (DLS) measurements, stability of the nanoparticles by Zeta potential and, by Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD)
Laccase production Laccase was obtained from T. versicolor and semi-purified following a previous published procedure (Cordi et al 2007; Leonowicz and Grzywnowicz 1981), and the silver nanoparticles were obtained after incubation in the presence of silver nitrate

Summary

Introduction

The literature has demonstrated that the mechanism used for the formation of metal nanoparticles is the action of a large number of enzymes secreted by fungi in special reductases (Ahmad et al 2003; Durán et al 2007; Durán et al 2011; Jain et al 2011). Sanghi et al (Sanghi et al 2001) demonstrated that the laccase enzyme secreted by Phanerochaete chrysosporium white-rot fungus was responsible for the formation of gold nanoparticles. Paraconiothyrium variabile was isolated from soil, and a blue enzyme with laccase activity was purified and characterized (Forootanfar et al 2011). This enzyme was able to produce gold nanoparticles (Faramarzi and Forootanfar 2011)

Objectives

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Results