Green synthesis of nanosilver particles by Aspergillus terreus HA1N and Penicillium expansum HA2N and its antifungal activity against mycotoxigenic fungi

Aims The aim of this study has been to synthesize silver nanoparticles (AgNPs) by an eco-friendly and low-cost method using of the fungi Aspergillus terreus HA1N and Penicillium expansum HA2N as an alternative to chemical procedures mostly requiring drastic experimental conditions emitting toxic chemicals byproduct. Also, this study has been extended to evaluate the effect of AgNPs on the growth of some mycotoxigenic fungi and ochratoxin A (OTA) produced by Aspergillus ochraceus. Methods and Results The AgNPs have been characterized by UV-Visible Spectrophotometer, Dynamic Light Scattering (DLS), Fourier Transform Infrared Spectroscopy (FTIR), and Transmission Electron Microscope (TEM). The TEM analysis has revealed that the size of AgNPs ranged between 14-25 nm in the case of P. expansum and 10-18 nm in the case of A. terreus. The antifungal activity of AgNPs colloids has indicated that the highest inhibition zone was detected with AgNPs synthesized by A. terreus HA1N against all tested fungi. The highest inhibition zone was detected with A. niger at the concentrations 3 and 6 μg of AgNPs solution (7.56±0.38 and 11.3 ±1.8 mm, respectively) while, A. ochraceus showed the maximum inhibition zone (16.33±0.96mm) at the concentration 9 μg of AgNPs synthesized by A. terreus. The results have also indicated that the AgNPs synthesized by A. terreus and P. expansum at the concentration 220 μg −100 mL media gave the highest reduction of OTA, where the percentages of reduction were 58.87% and 52.18, %, respectively. Conclusions The smallest size AgNPs synthesized by Aspergillus terreus HA1N are better in its antifungal activity against all tested mycotoxigenic fungi than the largest one synthesized by Penicillium expansum HA2N. Significance and Impact of the Study This is the first study focused on using AgNPs in control of OTA production. This article is protected by copyright. All rights reserved.