Application of the novel Cu-resistant fungus Aspergillus niger A3 in bioremoval of Cu-NPs from its aqueous solutions

Copper is an essential element for the metabolism of plants and animals, and has wide applications in the agricultural and industrial sectors. On the other hand, copper nanoparticles (Cu-NPs) have become widely used for research and application, which increases the chances of its spread and potential environmental exposure to this element. Therefore, in this study, the bioremediation bioreactor for the removing of Cu-NPs based on a fungal strain (Aspergillus niger) was introduced. A. niger isolate MR3 with accession No. OP861660.1 after molecular identification was selected as a promising isolate for copper resistance and Cu-NPs bioremoval. The impact of biomass age, pH, and contact time was investigated in order to establish the ideal biosorption conditions. The results showed a high Cu-NPs removal via two-days-old A. niger biomass, where the bioremoval percentage reached 66.8 % at pH value 7 after a contact time of 10 min. Dead biomass of A. niger achieved the highest Cu-NPs removal rate, eliminating 68.2 % compared with both living and alginate beads-immobilized biomass. Thus, bioremoval experiments using dead biomass were performed in a bioreactor for sequential removal of Cu-NPs. The bioremoval capacity reached 97 % under optimized conditions from synthetic wastewater after a contacting time of 10 min. Thus, the present work considered the first report for bioremediation of Cu-NPs into bioreactor.