Improving Immobilization of Pb(II) Ions by Aspergillus niger Cooperated with Photoelectron by Anatase Under Visible Light Irradiation

Lead pollution is rapidly becoming a serious concern, and remediation of lead contamination is a major challenge. Biological remediation is both environmentally friendly and sustainable process. In this study, we investigated the application of Aspergillus niger (Bpb1) for removing lead ion from a liquid medium by using photoelectron generated from a light-semiconductor mineral-microbial system. Synthetic anatase electrodes were systematically characterized and used as a photoelectron provider. Under light irradiation, the adsorption rates of Pb(II) by A. niger in the experimental groups increased by 204% (the maximum) on the fourth day, while the total adsorption rates remained the same. Further study of lead products revealed that lead ion combines with organic acids to form extracellular lead-containing products, which wrap around the fungal hyphae and combine with the cell wall. The anatase photoelectron enhanced the adsorption rate of Pb(II) by A. niger by forming larger lead-containing products, and by accelerating the transportation of Pb(II) into the inner cell. This novel approach provides newer insights into the application of biological degradation for environmental remediation.