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Lithium-bearing geothermal brine primary resource

Naturally occurring geothermal saline water containing dissolved lithium, considered as a geological extraction feed. The resource is a variable aqueous mixture, distinct from elemental lithium, a mineral species, manufactured lithium carbonate and waste-derived secondary resources. The curated experiment used one unsterilized brine from an unnamed Cornish geothermal project; its composition and laboratory response do not define all geothermal brines. No criticality designation or external material identifier is inferred from the lithium constituent.

Microbial & Biochemical Mechanisms (1)

Ureolytic carbonate precipitation during lithium-brine pretreatment

biomineralization Microbial

Associated Organisms: Sporosarcina pasteurii (NCBITaxon:1474)

Prepared S. pasteurii DSM 33 biomass with added urea raised pH and produced carbonate-bearing solids while measured Ca, Mg, Mn and Sr concentrations declined in one natural geothermal brine. Lithium largely remained in the measured solution. This is a laboratory impurity-removal pretreatment observation, not isolated lithium recovery or demonstrated improvement in downstream direct lithium extraction. The authors assigned calcite, vaterite and magnesite in mixed solids by XRD; phase-specific Sr/Mn incorporation and a uniquely cellular precipitation pathway were not established.

Experimental Context & Analytical Limits:
Cells grown in tryptone soy broth with 500 mM urea at 28 degrees C and 180 rpm were harvested in mid-log phase and washed with phosphate-buffered saline. The natural brine was not sterilized and was treated under reported non-growth conditions with 500 mM urea, initial OD600 values 0.05-0.4, 100 mL in 250 mL flasks, 28 degrees C, static incubation for 24 h, in triplicate. Figure 1 is the main comparison; supporting figures show higher inocula and a separate no-added-cell control. The reported Bacillus subtilis ATCC-2385 comparator and brine-plus-urea control are retained as source descriptions, without independently resolving that comparator strain accession. No matched-pH chemical or killed-biomass comparison was reported, and unsterilized brine is not an axenic system. ICP-OES measured elemental concentrations, but the main methods do not clearly specify solid/liquid separation for every metal time-point aliquot; supplementary Table S2 omits the lithium wavelength. Only qualitative treatment comparisons are curated. The paper does not demonstrate an integrated industrial process, a lithium carbonate product, or a lithium mass-balance recovery yield.
Curated Evidence Points:
Sections 4.1-4.2 identify the natural Cornish geothermal feed, DSM 33 preparation and flask conditions. Sections 2.1-2.2 and Figure 1 show culture-associated cation depletion with lithium retained; Figure 2 and Section 4.6 support characterization of mixed carbonate-bearing solids. The claim concerns this brine and prepared biomass under the reported conditions.
Table S1 characterizes the experimental brine, including lithium 75.2 +/- 1.8 mg/L (mean +/- SEM, n = 3); this is not a universal resource specification or an mg/kg observation. Figure S5 (pp. 21-22) compares inoculated brine with brine plus urea and no added cells. Figure S7 (p. 24), rather than the main text's misreferenced Figure S6, contains the authors' XRD assignment to calcite, vaterite and magnesite.
Section 2.1 says initial 10 minutes whereas Figure 1 axes and Section 4.2 sampling schedule use hours. Published Mg/Mn removal percentages do not consistently match the plotted Figure 1 series; its B. subtilis Mn control also declines despite the text's broad no-precipitation statement. No percentage or 10-minute rate is accepted here. Lithium retention does not establish extraction into a separate product; the cow-urine experiment used synthetic CaCl2 solution, distinct from the natural-brine assay.
The inoculated Mn/Sr trajectories in Figure S5 differ from Figure 1 and are not pooled as one replicated series. Table S9 labels retained lithium as recovery; this record treats it as aqueous retention. Table S7 reports negative magnesite saturation indices, unlike positive values stated in Section 2.2; model output is not accepted as independent confirmation of phase formation. Mixed-solid XRD identification remains an author assignment without purified phase yields.

Sources & References

  1. rehmanji2025: Rehmanji, Skeffington, Hudson-Edwards and Newsome (2025). Circular economy approaches to microbially-induced carbonate precipitation for bioprocessing of geothermal brine for lithium recovery. RSC Advances 15:43263-43274; DOI 10.1039/d5ra06824j, published 6 November 2025. Sections 2.1-2.2 and 4.1-4.7, Figure 1 and supplementary Tables S1-S2/S7, Figures S5/S7.
    https://doi.org/10.1039/d5ra06824j (accessed 2026-10-11)
  2. rehmanji2025_si: Rehmanji et al. (2025), supporting information to DOI 10.1039/d5ra06824j; 27-page RA-015-D5RA06824J-s001.pdf acquired in the EuropePMC supplementaryFiles archive. Tables S1-S2/S7 and Figures S5/S7.
    https://www.ebi.ac.uk/europepmc/webservices/rest/PMC12590475/supplementaryFiles (accessed 2026-10-11)
  3. dsm33: DSMZ catalogue, Sporosarcina pasteurii DSM 33, type strain, strain 22/Gibson 22; catalogue identity checked 2026-10-11.
    https://www.dsmz.de/collection/catalogue/details/culture/DSM-33 (accessed 2026-10-11)
  4. ncbi1474: NCBI Taxonomy 1474, Sporosarcina pasteurii, species; includes DSM 33 among type-strain collections.
    https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1474&mode=info (accessed 2026-10-11)

Curation History

Timestamp Curator Action Summary
2026-10-11T09:58:32Z codex (GPT-6; codex) CREATE Created the natural geothermal-brine resource identity and a qualified laboratory microbial pretreatment mechanism from the full primary paper and supplement. Preserved source timing, control, percentage and mineral-model conflicts without inventing lithium product recovery.

Record source: data/records/lithium-bearing-geothermal-brine.yaml