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Lanthanum element Critical Material

The element La, distinct from dissolved La(III), lanthanum chloride, lanthanum oxalate, lanthanum oxide and La-bearing minerals or wastes. The dated US designation concerns the named lanthanum mineral commodity; it does not transfer criticality to every La-bearing material. Laboratory evidence below concerns fungal production of a precipitation medium and separate chemical conversion of a precipitate, not extraction from an ore.

Identifiers & Classification

System Identifier Label
CHEBI CHEBI:33336 lanthanum atom

Criticality Designations

Jurisdiction List Name Edition / Document Classification Source
United States of America USGS Final List of Critical Minerals 2025; Federal Register 90:50494-50497, 7 November 2025 critical usgs2025

Microbial & Biochemical Mechanisms (1)

Lanthanum precipitation using Aspergillus niger culture supernatant

biomineralization Microbial

Associated Organisms: Aspergillus niger ATCC 1015 (NCBITaxon:380704)

A. niger ATCC 1015 cultures produced supernatants that precipitated La supplied as soluble lanthanum chloride. Recovered crystals included lanthanum oxalate decahydrate; higher-La supernatant reactions also produced a phosphorus-containing phase. Microbial involvement is the prior fungal culture step. Chemical oxalic acid also precipitated La, so the experiment does not establish a requirement for living cells during precipitation or a unique biological precipitation reaction.

Experimental Context & Analytical Limits:
Laboratory cultures used 100 mL nitrate-containing modified AP1 medium in 250 mL flasks, initially adjusted to pH 5.5, with 20 g/L glucose. Cultures were incubated for 7 days at 25 degrees C, 125 rpm, in darkness and filtered through 63 micrometre nylon mesh. The authors call this supernatant biomass-free; this coarse filtration is not a sterility demonstration. Harvest pH was 3.41 +/- 0.10. Assays mixed 9 mL supernatant with 1 mL LaCl3 solution to give 1-50 mM final La, then rolled for 24 h at room temperature, with at least three independent replicates. Precipitates were collected, washed three times and dried for weighing; remaining supernatant La was measured colorimetrically with Arsenazo III after centrifugation. Comparators used 9 mL of 25 mM chemical oxalic acid plus 1 mL LaCl3. These were not pH-matched supernatants, and the fungal-supernatant oxalate concentration was not directly measured. Neither mixed-REE separation, real-waste treatment nor industrial operation was demonstrated.
Curated Evidence Points:
Methods, Lanthanum biotransformation and Crystal yield and La assay, and Results, Biomass-free culture supernatant experiments, with Figure 7a,c, report 100% aqueous La removal at 1, 3 and 5 mM initial La and 49.8% at 15 mM. These are the authors' solution-removal percentages, not purified-element yields or independently established zero residual La. At 15 mM, the reported maximum dry precipitate mass was 23.3 mg per 10 mL reaction; this mass is not elemental La. Figures 4, 8 and 9 and the Discussion support oxalate precipitation with additional phosphorus-containing material at higher La loading.
Figure 7b,d and its accompanying results show that chemical oxalic acid controls also removed La, maintaining reported 100% removal through 11 mM initial La. Their different pH and unverified equivalence to the fungal oxalate concentration prevent an efficiency comparison normalized to precipitant dose. The article gives inconsistent formulas for the higher-La phosphorus phase in the results text and Figure 9, so no exact formula is assigned here. Figure 5 identifies La2(C2O4)3·10H2O from the separate 1 mM La agar experiment and La2O3 after heating those crystals to 1000 degrees C; the oxide conversion was a subsequent abiotic treatment, not a microbial redox reaction.

Sources & References

  1. chebi_lanthanum: ChEBI CHEBI:33336 - lanthanum atom; formula La, net charge 0
    https://www.ebi.ac.uk/chebi/CHEBI:33336 (accessed 2026-10-11)
  2. usgs2025: USGS (2025). Final 2025 List of Critical Minerals. Federal Register 90:50494-50497, document 2025-19813; lanthanum row on page 50496.
    https://www.govinfo.gov/content/pkg/FR-2025-11-07/html/2025-19813.htm (accessed 2026-10-11)
  3. kang2019: Kang, Csetenyi and Gadd (2019; published online 2018). Biotransformation of lanthanum by Aspergillus niger. Applied Microbiology and Biotechnology 103:981-993; Methods, Table 1 and Figures 3-9.
    https://doi.org/10.1007/s00253-018-9489-0 (accessed 2026-10-11)
  4. ncbi_niger_atcc1015: NCBI Taxonomy 380704 - Aspergillus niger ATCC 1015; strain-level no-rank node
    https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=380704 (accessed 2026-10-11)

Curation History

Timestamp Curator Action Summary
2026-10-11T05:19:12Z Codex (GPT-6; Codex) CREATE Added verified elemental identity, dated US2025 designation and bounded fungal-supernatant precipitation evidence after inspecting primary methods, results and figures; scientific review is recorded separately.

Record source: data/records/lanthanum.yaml