Role of indigenous microbial communities in the mobilization of potentially toxic elements and rare-earth elements from alkaline mine waste

S Cebekhulu; A Gómez-Arias; A Matu; J Alom; A Valverde; M A Caraballo; O Ololade; P Schneider; J Castillo

doi:10.1016/j.jhazmat.2024.133504

Role of indigenous microbial communities in the mobilization of potentially toxic elements and rare-earth elements from alkaline mine waste

J Hazard Mater. 2024 Mar 15:466:133504. doi: 10.1016/j.jhazmat.2024.133504. Epub 2024 Jan 11.

Authors

S Cebekhulu¹, A Gómez-Arias², A Matu³, J Alom³, A Valverde⁴, M A Caraballo⁵, O Ololade¹, P Schneider⁶, J Castillo⁷

Affiliations

¹ Centre for Environmental Management, University of the Free State, Bloemfontein, Republic of South Africa.
² Department of Chemistry, University of the Free State, Bloemfontein, Republic of South Africa.
³ Department of Microbiology and Biochemistry, University of the Free State, Bloemfontein, Republic of South Africa.
⁴ Instituto de Recursos Naturales y Agrobiologıa de Salamanca (IRNASA, CSIC), Salamanca, Spain.
⁵ Department of Mining, Mechanic, Energetic and Construction Engineering, Higher Technical School of Engineering, University of Huelva, Huelva, Spain; Department of Water, Mining and Environment, Scientific and Technological Center of Huelva, University of Huelva, Huelva, Spain.
⁶ Department for Water, Environment, Civil Engineering and Safety, University of Applied Sciences Magdeburg-Stendal, Magdeburg, Germany.
⁷ Department of Microbiology and Biochemistry, University of the Free State, Bloemfontein, Republic of South Africa. Electronic address: CastilloHernandezJ@ufs.ac.za.

PMID: 38310848
DOI: 10.1016/j.jhazmat.2024.133504

Abstract

This study aims to evaluate the role of indigenous microorganisms in the mobilization of potentially toxic elements (PTE) and rare-earth elements (REE), the influence of the bioavailability of carbon sources that might boost microbial leaching, and the generation of neutral/alkaline mine drainage from alkaline tailings. These tailings, with significant concentrations of total organic carbon (TOC), were mainly colonized by bacteria belonging to the genera Sphingomonas, Novosphingobium and Solirubrobacter, and fungi of the genera Alternaria, Sarocladium and Aspergillus. Functionality analysis suggests the capability of these microorganisms to leach PTE and REE. Bio-/leaching tests confirmed the generation of neutral mine drainage, the influence of organic substrate, and the leaching of higher concentrations of PTE and REE due to the production of organic acids and siderophores by indigenous microorganisms. In addition, this study offers some insights into a sustainable alternative for reprocessing PMC alkaline tailings to recover REE.

Keywords: Alkaline mine tailings; Indigenous microorganisms; Metal mobility; Organic acids; Siderophores; Total organic carbon.

MeSH terms

Bacteria / metabolism
Carbon / metabolism
Metals, Rare Earth* / metabolism

Substances

Metals, Rare Earth
Carbon