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Asbolane mineral

Asbolane is a hydrous manganese oxide mineral with variable associated hydroxide cations, listed as grandfathered with historical year 1841 in the September 2026 IMA-CNMNC list. Its listed formula is Mn4+(O,OH)2·(Co,Ni,Mg,Ca)x(OH)2x·nH2O. It is distinct from elemental manganese, cobalt and nickel, from lateritic ore, and from an arbitrary cobalt-doped birnessite preparation. The experiment below uses a synthetic Co/Ni-bearing powder that the source assigns to asbolane by XRD; no independent refinement establishes ideal composition or complete phase purity. No commodity criticality is inherited.

Microbial & Biochemical Mechanisms (1)

Geobacter-associated reductive transformation of synthetic Co/Ni-asbolane

redox transformation Microbial

Associated Organisms: Geobacter sulfurreducens (NCBITaxon:35554)

A laboratory culture identified as Geobacter sulfurreducens altered a source-assigned synthetic Co/Ni-asbolane preparation under anaerobic conditions. Cell-containing treatments released more centrifuged-supernatant Mn, Co and Ni than no-cell controls, while mixed reduced manganese phases appeared and solid-associated Mn spectra shifted toward lower valence. Manganese in solution subsequently declined, and most of the cobalt remained outside the measured aqueous fraction. This supports a culture-associated transformation with partial metal mobilization and retention, not complete extraction, a phase-pure recovery product, an established enzyme-specific mechanism or industrial deployment.

Experimental Context & Analytical Limits:
Buchanan's laboratory culture collection supplied Geobacter sulfurreducens without a strain accession. Living cells were grown anaerobically at 30 degrees C with acetate/fumarate, harvested in late logarithmic phase and washed three times in 30 mM bicarbonate buffer at pH 7.1 under N2:CO2 80:20. The experiment used a 5 mL aliquot of synthetic Co/Ni-asbolane suspension (stock nominally 2 mmol/L Mn in 10 mM bicarbonate at circumneutral pH), added sodium acetate at reported 10 mM and cells to final OD600 0.6, incubated anaerobically in the dark at 30 degrees C. The added cell volume and precise final mineral concentration are not reported. The synthetic feed was precipitated from Co/Ni/Mn chlorides with KMnO4/KOH, washed in alkaline NaCl and stored at 4 degrees C. Its asbolane designation is source-assigned; the thesis acknowledges structural uncertainty and mixed Mn oxidation states. No-cell controls contained the same mineral suspension and acetate. Sampling used aseptic anaerobic handling; residual slurry was dried anaerobically before powder XRD. No-cell diffraction patterns, killed-cell mineral controls or a demonstrated drying-independent phase assignment are supplied.
Curated Evidence Points:
Chapter 4 preparation methods on printed page 123 and Figure 4.2a (page 131) assign the starting synthetic powder to asbolane. Figures 4.1-4.4 and Results on pages 127-135 show the culture-associated aqueous-metal trends, appearance of source-assigned pyrochroite/rhodochrosite with transient feitknechtite, and changing Mn spectra. The source uses this preparation as a model for natural cobalt-bearing manganese oxides; its results do not demonstrate identical behavior of natural asbolane or lateritic ore.
Chapter 4 methods and Figure 4.1 (printed pages 123-128) show cell-associated dissolved-metal release above no-cell controls, followed by declining aqueous Mn between 17 and 72 hours. These are centrifuged-supernatant ICP-MS measurements, not direct aqueous valence measurements or isolated product recovery. Biological ICP-MS samples at 1 and 17 hours are described as triplicate, 72 hours as one sacrificial bottle, and controls as duplicate; Figure 4.1 includes 24 hours but its replication is unspecified. Neither aqueous loss nor retained metal establishes allocation to this particular mineral.
Figure 4.2 (printed page 131) presents labelled mixed-phase patterns without quantitative phase refinement, phase-specific mass balance or a matched no-cell mineral time series. Pyrochroite and feitknechtite have overlapping low-angle peaks, so the accepted claim is the author's assignment, not independently re-refined purity. Figure 4.3 and pages 129-130 show cell-associated particles and heterogeneous elemental spectra; the 17-hour laths are only tentatively linked to the two phases. Elemental co-occurrence does not identify a unique cobalt/nickel host or prove lattice incorporation.
Figures 4.4-4.8, the tables on printed pages 146-147 and Appendix 4.1-4.2 support a heterogeneous shift toward lower manganese valence. Fitted oxidation-state fractions carry the author's stated 10% error and differ substantially between surface-sensitive bulk measurements and spatially restricted transmission SXM. Only one imaged region per time point was possible, and coherent SXM data are absent at 72 hours. These are spectral fractions, not mineral abundances or conversion yields. A sequential one-electron pathway and direct cell-surface cytochrome participation remain interpretations; no enzyme perturbation or phase-specific electron-transfer test was performed.
Source inconsistencies remain unresolved: the tables discussed as 4.1/4.2 are printed as 6.1/6.2; the 17-hour co-located Mn average differs between the main table and appendix/text; regional counts differ across captions; Appendix Table 4.2 says Mn in its caption but tabulates Co. Chapter 3 enrichment acetate wording differs from its medium table. The conclusion prints Mn(VI) where the chapter investigates Mn(IV). No corrected speciation series, growth-medium recipe or unique kinetic pathway is inferred from these discrepancies.
Context_only Source: ncbi_geobacter
NCBI 35554 resolves Geobacter sulfurreducens at species rank. It neither identifies the thesis's stock as strain PCA nor establishes mineral transformation by every member of this species.
Results on pages 139-140 explicitly leave the cobalt-reduction route unresolved: cobalt could be reduced directly in association with cells or after dissociation by newly reduced manganese phases. The aqueous ICP-MS signal does not measure dissolved cobalt valence. Solid-associated cobalt detection cannot distinguish adsorption, incorporation or allocation among the coexisting phases. The source's reduction and retention interpretation therefore does not establish a unique cobalt extraction pathway.

Sources & References

  1. ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026. Asbolane row PDF page 16, status G and year 1841; definitions on pages 1-2.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-14)
  2. buchanan_thesis: Buchanan, Dawn Melisa. The bioreduction of cobalt and nickel bearing manganese minerals. University of Manchester PhD thesis, cover dated 2021; repository award date 11 January 2022. Chapter 4, printed pages 115-158 (PDF pages 116-159), including Figures 4.1-4.8 and appendix figures/tables; Chapter 3 methods.
    https://pure.manchester.ac.uk/ws/portalfiles/portal/261215972/FULL_TEXT.PDF (accessed 2026-10-14)
  3. buchanan_repository: University of Manchester Research Explorer. Buchanan thesis metadata and original file; award date 11 January 2022. This is a thesis, not evidence of subsequent journal publication.
    https://research.manchester.ac.uk/en/studentTheses/the-bioreduction-of-cobalt-and-nickel-bearing-manganese-minerals/ (accessed 2026-10-14)
  4. ncbi_geobacter: NCBI Taxonomy 35554. Geobacter sulfurreducens, species rank; identity context only, not authentication of the unspecified Manchester laboratory stock.
    https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=35554&mode=Info (accessed 2026-10-14)
  5. asbolane_handbook: Handbook of Mineralogy, Asbolane. Mineral Data Publishing 2001-2005 version 1; one-page mineral identity and variable composition, not authentication of the experimental feed.
    https://www.handbookofmineralogy.org/pdfs/asbolane.pdf (accessed 2026-10-14)

Curation History

Timestamp Curator Action Summary
2026-10-14T09:20:09Z codex (GPT-6; codex) CREATE Added asbolane identity and source-qualified synthetic-feed reductive transformation by a Geobacter culture, retaining partial mobilization, source discrepancies and uncertain cobalt fate.

Record source: data/records/asbolane.yaml