Bioremoval of PVP-coated silver nanoparticles using Aspergillus niger: the role of exopolysaccharides

Abstract

Extensive use of engineered nanoparticles has led to their eventual release in the environment. The present work aims to study the removal of Polyvinylpyrrolidone-coated silver nanoparticles (PVP-Ag-NPs) using Aspergillus niger and depict the role of exopolysaccharides in the removal process. Our results show that the majority of PVP-Ag-NPs were attached to fungal pellets. About 74% and 88% of the PVP-Ag-NPs were removed when incubated with A. niger pellets and exopolysaccharide-induced A. niger pellets, respectively. Ionized Ag decreased by 553 and 1290-fold under the same conditions as compared to stock PVP-Ag-NP. PVP-Ag-PVP resulted in an increase in reactive oxygen species (ROS) in 24 h. Results show an increase in PVP-Ag-NPs size from 28.4 to 115.9 nm for A. niger pellets and 160.3 nm after removal by stress-induced A. niger pellets and further increased to 650.1 nm for in vitro EPS removal. The obtained findings show that EPS can be used for nanoparticle removal, by increasing the net size of nanoparticles in aqueous media. This will, in turn, facilitate its removal through conventional filtration techniques commonly used at wastewater treatment plants. Supplementary Information The online version contains supplementary material available at 10.1007/s11356-021-18018-9.

Heavy metal resistant Aspergillus species from soil and water environments impacted by solid wastes dumping exhibit mycoremediative traits

“…Hence, they produce several intracellular and extracellular enzymes that can eliminate heavy metal contaminants through metal cation adsorption with functional fungal cell wall groups, complexation, ion exchange, etc. (Tomasini and León-Santiesteban 2019;Ayele et al, 2021;Gomaa et al, 2022;Muksy and Kolo, 2023).…”

Biosorption performance of the multi-metal tolerant fungus Aspergillus sp. for removal of some metallic nanoparticles from aqueous solutions

“…However, these altered properties, together with NPs' extremely small size, may also increase the material's bioavailability and toxicity [ 6 ]. The toxicity may be absorbed by the skin, lungs, or gastrointestinal tract and may result in secondary toxicity by way of oxidative stress, inflammation, DNA damage, apoptosis, or translocation inside organs and tissues [ 9 ]. Therefore, it is important to create a quick and efficient way to eliminate NPs before releasing them into the environment [ 10 ].…”

“…Fungi can also be readily produced in large quantities using basic fermentation methods and low-cost growing substrates. Fungi can eliminate heavy metals and other contaminants by complexing, exchanging ions, or physically adsorbing the metal cations with functional fungal cell wall groups [ 9 , 14 ]. It should be noted that various fermentation industries produce large amounts of fungal biomass as waste, which can be used as heavy metal biological adsorbents.…”