Bayan Obo REE Tailings Consortium

Ecological State ENGINEERED

Environment mine tailing
ENVO:00000072

Source File Bayan_Obo_REE_Tailings_Consortium.yaml

An acid-producing bacterial consortium engineered to extract rare earth elements (REE) from tailings at the Bayan Obo mine in Inner Mongolia, China, the world's largest rare earth deposit. This functional bacterial consortium achieves exceptional REE recovery rates of 82-83% for the five main light rare earth elements (La, Ce, Pr, Nd, Sm) after 18 days of bioleaching using one-step or two-step processes. The tailings are iron extraction residues from medium-poor oxidized ores containing bastnaesite (REE(CO₃)F) and monazite as primary REE minerals. The consortium employs acid-producing bacteria including actinomycetes (Streptomyces sp.), autotrophic acidophiles (Acidithiobacillus ferrooxidans), and heterotrophic acidophiles (Acidiphilium cryptum) that work synergistically to mobilize REE through acidolysis and organic acid complexation. Key mechanisms include production of organic acids (citric, oxalic, lactic, pyruvic), siderophores, and complexing ligands that solubilize REE from carbonate-fluoride minerals. The two-step process (sequential inoculation with heterotrophs followed by autotrophs) achieves 83.51% recovery versus 82.78% for one-step (simultaneous inoculation), demonstrating synergistic enhancement through pH control and organic acid accumulation. This system represents a critical sustainable biotechnology for recovering strategic REE materials essential for clean energy technologies, permanent magnets, and electronics while remediating millions of tons of existing Bayan Obo tailings.

Taxonomy

Taxon	Ontology ID	Functional Roles	Abundance
Acidithiobacillus ferrooxidans	NCBITaxon:920	PRIMARY_DEGRADER	ABUNDANT
Acidiphilium cryptum	NCBITaxon:524	SYNTROPHIC_PARTNER SECONDARY_FERMENTER	ABUNDANT
Streptomyces	NCBITaxon:1883	PRIMARY_DEGRADER CROSS_FEEDER	COMMON

Ecological Interactions

Sulfuric Acid Generation and pH Reduction

COMMENSALISM

Source Taxon: Acidithiobacillus ferrooxidans

Metabolites: sulfuric acid (CHEBI:26836), Fe(II) (CHEBI:29033), Fe(III) (CHEBI:29034)

Biological Processes:

oxidation-reduction process (GO:0055114)
sulfur compound metabolic process (GO:0006790)

Downstream Effects:

→ REE Dissolution from Bastnaesite and Monazite

Evidence

doi:10.1016/j.cej.2024.153492 - SUPPORT (IN_VITRO)

"The development of efficient environmental cleanup materials is a crucial scientific and technological concern"

Organic Acid Production and REE Complexation

MUTUALISM

Source Taxon: Acidiphilium cryptum

Metabolites: citric acid (CHEBI:30769), oxalic acid (CHEBI:16995), lactic acid (CHEBI:28358), pyruvic acid (CHEBI:32816)

Biological Processes:

organic acid metabolic process (GO:0006082)
carboxylic acid biosynthetic process (GO:0046394)

Downstream Effects:

→ REE Dissolution from Bastnaesite and Monazite

Evidence

doi:10.1016/j.chemogeo.2018.03.018 - SUPPORT (IN_VITRO)

"actinobacterial strains secreted various organic acids, complexing ligands, and siderophores as dominant agents"

REE Dissolution from Bastnaesite and Monazite

MUTUALISM

Metabolites: lanthanum(3+) (CHEBI:32359), cerium(3+) (CHEBI:32998), praseodymium(3+) (CHEBI:49648), neodymium(3+) (CHEBI:33372), samarium(3+) (CHEBI:33376)

Biological Processes:

metal ion transport (GO:0030001)

Downstream Effects:

→ Sulfuric Acid Generation and pH Reduction

→ Organic Acid Production and REE Complexation

Evidence

doi:10.1016/j.cej.2024.153492 - SUPPORT (IN_VITRO)

"Since the groundbreaking work on Ti3C2Tx in 2011, there has been a huge growing interest in MXene-based composites developed through heterointerface engineering due to its high surface area, hydrophilicity, eco-friendliness, biocompatibility, easy functionalization, excellent thermal/mechanical properties, metal conductivity and rich electronic density"
doi:10.1016/j.cej.2024.153492 - SUPPORT (IN_VITRO)

"rare earth elements in Bayan Obo RERT could be high-efficiently bioleached by acid bioleaching functional bacteria consortium"

Synergistic Two-Step Process Enhancement

MUTUALISM

Source Taxon: Acidiphilium cryptum

Biological Processes:

mutualism (GO:0044403)

Evidence

doi:10.1016/j.cej.2024.153492 - SUPPORT (IN_VITRO)

"In the area of environmental remediation, MXene-based composites obtained through heterointerface engineering strategies have the ability to effectively remove and systematically monitor contaminants in comparison to virgin MXene, thanks to the synergistic effects and complementary benefits"

Environmental Factors

Factor	Value	Unit
pH	1.5-2.5	pH units
Bioleaching Duration	18	days
Tailings Source and Composition	15 million tons	metric tons
Target REE Elements	La, Ce, Pr, Nd, Sm	N/A
Temperature	~30	°C
Process Configuration	One-step vs. two-step	N/A
Mineral Targets	Bastnaesite and monazite	N/A