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Mixed Gallium LED Recovery Consortium

Ecological State ENGINEERED
Environment contaminated soil
ENVO:00002874
Source File Mixed_Gallium_LED_Recovery_Consortium.yaml

An engineered acidophilic microbial consortium specifically designed for recovering gallium from waste light-emitting diodes (LEDs) through non-contact bioleaching. This mixed community consists of three iron- and sulfur-oxidizing bacteria in equal proportions (1:1:1 ratio): Acidithiobacillus thiooxidans, Acidithiobacillus ferrooxidans, and Leptospirillum ferrooxidans. The consortium produces biogenic lixiviants - primarily sulfuric acid (H₂SO₄) from sulfur oxidation and ferric iron (Fe³⁺) from iron oxidation - that solubilize gallium from GaN-based LED materials without direct contact between microbes and solid waste. Operating at pH 1.0-1.5 and 15 g/L pulp density, the system achieves exceptional 99.5% gallium leaching efficiency within just 3 days. The non-contact bioleaching approach separates the bioreactor (where microbes generate lixiviants) from the leaching reactor (where acids attack LED waste), preventing microbial inhibition by toxic LED components while enabling gallium recovery. In addition to gallium, the process recovers copper and nickel from LED substrates and interconnects. This biotechnological platform offers a sustainable alternative to harsh chemical leaching methods, utilizing microbial metabolism to extract critical materials from electronic waste while avoiding toxic emissions and reducing environmental impact.

Taxonomy

Taxon Ontology ID Functional Roles Abundance
Acidithiobacillus thiooxidans NCBITaxon:930
PRIMARY_DEGRADER PRIMARY_PRODUCER
ABUNDANT
Acidithiobacillus ferrooxidans NCBITaxon:920
PRIMARY_PRODUCER PRIMARY_DEGRADER
ABUNDANT
Leptospirillum ferrooxidans NCBITaxon:180
PRIMARY_PRODUCER PRIMARY_DEGRADER
ABUNDANT

Ecological Interactions

Biogenic Sulfuric Acid Production for Gallium Leaching

MUTUALISM

Source Taxon: Acidithiobacillus thiooxidans

Metabolites: sulfur (CHEBI:26833), sulfuric acid (CHEBI:26836), gallium(3+) (CHEBI:49631)

Biological Processes:

Evidence

Ferric Iron Generation for Multi-Metal Recovery

CROSS_FEEDING

Source Taxon: Acidithiobacillus ferrooxidans

Metabolites: Fe(II) (CHEBI:29033), Fe(III) (CHEBI:29034), copper(2+) (CHEBI:29036), nickel(2+) (CHEBI:49786)

Biological Processes:

Evidence

  • doi:10.1016/j.jece.2025.120403 - SUPPORT (IN_VITRO)
    "Enrichment of autohydrogenotrophic and sulfide-oxidizing autotrophic denitrifiers, and nitrate dependent iron oxidation bacteria by bioelectricity all promoted denitrification"

Synergistic Lixiviant Production in Mixed Consortium

MUTUALISM

Metabolites: sulfuric acid (CHEBI:26836), Fe(III) (CHEBI:29034), gallium(3+) (CHEBI:49631)

Biological Processes:

Evidence

  • doi:10.1016/j.jece.2025.120403 - SUPPORT (IN_VITRO)
    "Enrichment of autohydrogenotrophic and sulfide-oxidizing autotrophic denitrifiers, and nitrate dependent iron oxidation bacteria by bioelectricity all promoted denitrification"
  • doi:10.1016/j.jece.2025.120403 - SUPPORT (IN_VITRO)
    "99.5% Ga leaching efficiency within 3 days at 15 g/L pulp density"

Non-Contact Bioleaching System Design

COMMENSALISM

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

Biological Processes:

Evidence

  • doi:10.1016/j.jece.2025.120403 - SUPPORT (IN_VITRO)
    "In this study, constructed wetland-microbial fuel cell (CW-MFC) filled with modified basalt fiber (MBF) via iron modification was utilized for treating perfluorooctanoic acid (PFOA) containing sewage"
  • doi:10.1016/j.jece.2025.120403 - SUPPORT (IN_VITRO)
    "preventing microbial inhibition by toxic LED components while enabling gallium recovery"

Environmental Factors

Factor Value Unit
Extreme Acidity for Gallium Dissolution 1.0-1.5 pH
LED Waste Pulp Density 15 g/L
Rapid Leaching Duration 3 days
Mesophilic Temperature ~30 °C
Publication Recency 2025 year