Effects of mycogenic silver nanoparticles on organisms of different trophic levels

Biogenic silver nanoparticles (AgNPs) are considered a promising alternative to their synthetic versions. However, the environmental impact of such nanomaterials is still scarcely understood. Thus, the present study aims at assessing the antimicrobial action and ecotoxicity of AgNPs biosynthesized by the fungus Aspergillus niger IBCLP20 towards three freshwater organisms: Chlorella vulgaris, Daphnia similis, and Danio rerio (zebrafish). AgNPs IBCLP20 showed antibacterial action against Klebsiella pneumoniae between 5 and 100 μg mL−1, and antifungal action against Trichophyton mentagrophytes in concentrations ranging from 20 to 100 μg mL−1. The cell density of the microalgae Chlorella vulgaris decreased 40% after 96 h of exposure to AgNPs IBCLP20, at the highest concentration analysed (100 μg L−1). The 48 h median lethal concentration for Daphnia similis was estimated as 4.06 μg L−1 (2.29–6.42 μg L−1). AgNPs IBCLP20 and silver nitrate (AgNO3) caused no acute toxicity on adult zebrafish, although they did induce several physiological changes. Mycosynthetized AgNPs caused a significant increase (p