Effects of pH, temperature and agitation on the biosynthesis of iron nanoparticles produced by Trichoderma species

Abstract

There is an increasing global search for commercially and environmentally clean synthesis of metallic nanoparticles from bioresources. However, there is insufficient reported information on the production of iron nanoparticles (FeNPs) from fungi such as Trichoderma species which has potentials for greater for yield of FeNPs as compared with bacterial sources. Filtrates obtained from biomass of pure cultures grown (72 h) in Potato Dextrose Broth were reacted with 1 M ferric chloride solution. A change in coloration monitored by ultraviolet-visible spectrophotometer (200-600 nm) as compared with control (ferric chloride solution) indicated a positive result. Nanoparticle synthesized in the reactive filtrate was characterized using utltraviolet-visible spectroscopy and Fourier transform infrared spectroscopy (FTIR). The effects of some physical parameters such as agitation, pH and temperature were monitored. The UV-vis spectrum revealed the peak of absorbance of synthesized nanoparticle by selected Trichoderma species at 275 nm. Optimum conditions for nanoparticle biosynthesis were observed at pH 4.5, 35 °C and when cells were agitated. Peaks of transmittance were observed at 950, 1800, 2250, 3000 and 3500 cm-1. These peaks represent the C-H, C=O, C=N, C=H and the OH functional groups respectively. The presence of the alkene, carboxyl and phenol groups suggests a capping of the NPs by the organism after redox reaction. The properties of extracellular iron nanoparticles synthesized by Trichoderma species from this study, presents the fungi as a bioresource for synthesis of stable NPs.