Bayan Obo REE Tailings Consortium

Community ID CommunityMech:000005

Ecological State ENGINEERED

Environment mine tailing
ENVO:00000003

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
PMID:38310848 - PARTIAL (IN_VIVO) "Functionality analysis suggests the capability of these microorganisms to leach PTE and REE" doi:10.1016/j.cej.2024.153492 - SUPPORT (IN_VITRO) "acid bioleaching functional bacteria consortium"
Acidiphilium cryptum	NCBITaxon:524	SYNTROPHIC_PARTNER SECONDARY_FERMENTER	ABUNDANT
Streptomyces	NCBITaxon:1883	PRIMARY_DEGRADER CROSS_FEEDER	COMMON
doi:10.1016/j.chemogeo.2018.03.018 - SUPPORT (IN_VITRO) "Streptomyces sp. strain growing in an oligotrophic medium and leaching as much as 548 μg/L total REEs" doi:10.1016/j.chemogeo.2018.03.018 - SUPPORT (IN_VITRO) "actinobacterial strains secreted various organic acids, complexing ligands, and siderophores as dominant agents to extract rare earth elements from bastnaesite-bearing rock"

Ecological Interactions

Taxon

Cross-feeding

Mutualism

Syntrophy

Competition

Commensalism

Niche partitioning

Colonization facilitation

Strain competition

Predation

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:

sulfur compound metabolic process (GO:0006790)

Downstream Effects:

→ REE Dissolution from Bastnaesite and Monazite

Evidence

PMID:38310848 - PARTIAL (IN_VIVO)

"leaching of higher concentrations of PTE and REE due to the production of organic acids and siderophores by indigenous microorganisms"

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

Source Taxon: Acidithiobacillus ferrooxidans

Target Taxon: Acidiphilium cryptum

Metabolites: lanthanum(3+) (CHEBI:49701), cerium(3+) (CHEBI:48782), praseodymium(3+) (CHEBI:229784), neodymium(3+) (CHEBI:229785), samarium(3+) (CHEBI:49890)

Biological Processes:

metal ion transport (GO:0030001)

Downstream Effects:

→ Sulfuric Acid Generation and pH Reduction

→ Organic Acid Production and REE Complexation

Evidence

PMID:38702568 - PARTIAL (REVIEW)

"The review outlines the principles and distinctions of bioleaching, biosorption, and bioaccumulation, offering a comparative analysis of their potential and limitations"
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

Target Taxon: Acidithiobacillus ferrooxidans

Biological Processes:

mutualism (GO:0044403)

Evidence

PMID:38310848 - PARTIAL (IN_VIVO)

"the influence of the bioavailability of carbon sources that might boost microbial leaching"

Actinobacterial Siderophore and Organic Acid Contribution

SYNTROPHY

Source Taxon: Streptomyces

Target Taxon: Acidiphilium cryptum

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

Biological Processes:

organic acid metabolic process (GO:0006082)
siderophore biosynthetic process (GO:0019290)

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 to extract rare earth elements from bastnaesite-bearing rock"

Environmental Factors

Factor	Value	Unit
pH	1.5-2.5	pH units
PMID:38702568 - PARTIAL (REVIEW) "The review outlines the principles and distinctions of bioleaching, biosorption, and bioaccumulation"
Bioleaching Duration	18	days
PMID:38310848 - PARTIAL (IN_VIVO) "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"
Tailings Source and Composition	15 million tons	metric tons
PMID:38310848 - PARTIAL (IN_VIVO) "These tailings, with significant concentrations of total organic carbon (TOC), were mainly colonized by bacteria belonging to the genera Sphingomonas, Novosphingobium and Solirubrobacter"
Target REE Elements	La, Ce, Pr, Nd, Sm	N/A
PMID:38702568 - PARTIAL (REVIEW) "successful methods, including advanced techniques for enhancing microbial strains to achieve higher REE recovery"
Temperature	~30	°C
Process Configuration	One-step vs. two-step	N/A
PMID:38702568 - PARTIAL (REVIEW) "principles and distinctions of bioleaching, biosorption, and bioaccumulation, offering a comparative analysis of their potential and limitations"
Mineral Targets	Bastnaesite and monazite	N/A
PMID:38310848 - PARTIAL (IN_VIVO) "a sustainable alternative for reprocessing PMC alkaline tailings to recover REE"