Removal and biomineralization of Pb2+ in water by fungus Phanerochaete chrysoporium. (1st July 2020) - Zhao, Wei-Wei
Abstract: The removal and biomineralization of Pb 2+ (200 mg/L) in water were investigated utilizing mature mycelia of Phanerochaete chrysoporium . Mycelial dosage, initial Pb 2+ concentration, solution pH and treatment time all were shown to have an influence on Pb 2+ removal. Granular, lead-containing precipitation was formed on the fungal hyphae upon exposure to lead nitrate, which was confirmed from scanning electron micrograph/Energy Dispersive Spectrometer (SEM/EDS). Energy dispersive X-ray spectroscopic analysis revealed the presence of lead (48.5% by weight) along with phosphorus in the precipitate. This extracellular precipitate was further identified as pyromorphite lead hydroxyphosphate [Pb5 (PO4 )3 OH] by X-ray powder diffraction (XRD) analysis. During Pb 2+ removal, size-enlarged mineral precipitation, and clustered nanospherical particles formed on the hyphae were revealed by SEM/XRD. A remarkable increase of mycelial phosphatase activity of 1.5 times that of the control and decreased phosphate concentration in solution (16.76 mg/L to 1.39 mg/L) initially upon exposure to Pb 2+ suggested that phosphatase may hydrolyze organic phosphorus into inorganic phosphate and release it into solution, participating in the biomineralization of Pb 2+ . Toxicity tests showed that the toxicity of Pb 2+ polluted water decreased after treatment. The results clearly demonstrate previously unknown lead biomineralization as pyromorphite through fungal phosphatase. Graphical abstract: Image 1055115 Highlights: Lead pollution poses a potential threat to human health and the environment. The removal and biomineralization of Pb 2+ in water was performed by fungus P. chrysoporium. XRD analysis demonstrated that Pb 2+ was mineralized into Pb5 (PO4 )3 OH. The process involves the hydroxylation of organic phosphorus by phosphatase. The Pb 2+ mineralization to Pb5 (PO4 )3 OH by a fungus has been shown firstly.