title: Fungal Bioweathering of Mimetite and a General Geomycological Model for Lead Apatite Mineral Biotransformations.
abstract: Fungi play important roles in biogeochemical processes such as organic matter decomposition, bioweathering of minerals and rocks, and metal transformations and therefore influence elemental cycles for essential and potentially toxic elements, e.g., P, S, Pb, and As. Arsenic is a potentially toxic metalloid for most organisms and naturally occurs in trace quantities in soil, rocks, water, air, and living organisms. Among more than 300 arsenic minerals occurring in nature, mimetite [Pb5(AsO4)3Cl] is the most stable lead arsenate and holds considerable promise in metal stabilization for in situ and ex situ sequestration and remediation through precipitation, as do other insoluble lead apatites, such as pyromorphite [Pb5(PO4)3Cl] and vanadinite [Pb5(VO4)3Cl]. Despite the insolubility of mimetite, the organic acid-producing soil fungus Aspergillus niger was able to solubilize mimetite with simultaneous precipitation of lead oxalate as a new mycogenic biomineral. Since fungal biotransformation of both pyromorphite and vanadinite has been previously documented, a new biogeochemical model for the biogenic transformation of lead apatites (mimetite, pyromorphite, and vanadinite) by fungi is hypothesized in this study by application of geochemical modeling together with experimental data. The models closely agreed with experimental data and provided accurate simulation of As and Pb complexation and biomineral formation dependent on, e.g., pH, cation-anion composition, and concentration. A general pattern for fungal biotransformation of lead apatite minerals is proposed, proving new understanding of ecological implications of the biogeochemical cycling of component elements as well as industrial applications in metal stabilization, bioremediation, and biorecovery.
authors.affiliation: Geomicrobiology Group, College of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom Laboratorio Biodiversità dei Funghi, Dipartimento di Biologia Ambientale, Sapienza Università di Roma, Rome, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Ceci
authors.affiliation: Electron Microscopy, Central Imaging Facility, Centre for Advanced Scientific Technologies, College of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom.
authors.forename: Martin
authors.initials: M
authors.lastname: Kierans
authors.affiliation: The James Hutton Institute, Craigiebuckler, Aberdeen, Scotland, United Kingdom Department of Soil and Environment, Swedish University of Agricultural Sciences, Uppsala, Sweden.
authors.forename: Stephen
authors.initials: S
authors.lastname: Hillier
authors.affiliation: Laboratorio Biodiversità dei Funghi, Dipartimento di Biologia Ambientale, Sapienza Università di Roma, Rome, Italy.
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Persiani
authors.affiliation: Geomicrobiology Group, College of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, People's Republic of China g.m.gadd@dundee.ac.uk.
authors.forename: Geoffrey Michael
authors.initials: GM
authors.lastname: Gadd
mesh_terms: D001031:Apatites / Q000378:metabolism*; D001152:Arsenicals / Q000378:metabolism*; D001234:Aspergillus niger / Q000378:metabolism*; D001669:Biochemical Phenomena; D001711:Biotransformation; D007854:Lead / Q000378:metabolism*; D053858:Metabolic Networks and Pathways; D008903:Minerals / Q000378:metabolism*
chemical_list: D001031:Apatites; D001152:Arsenicals; D008903:Minerals; C560237:mimetite; D007854:Lead