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Anatase mineral

Anatase is the TiO2 mineral species listed by IMA-CNMNC in September 2026 with approved status A and the designation 1962 s.p. The latter denotes a special procedure, not a numbered approval identifier. Anatase is distinct from rutile and brookite despite their common ideal formula, and from elemental titanium, titanium-bearing ores and unspecified TiO2 nanoparticles. The curated experiment concerns a manufactured anatase counterpart produced using engineered bacterial biomass, a soluble titanium reagent and subsequent heat treatment. It does not establish microbial formation of natural anatase, dissolution of a natural titanium mineral or recovery of titanium from an ore or waste. No constituent-derived criticality is asserted.

Microbial & Biochemical Mechanisms (1)

Engineered bacterial template followed by thermal anatase synthesis

other Microbial

Associated Organisms: Escherichia coli (NCBITaxon:562)

Escherichia coli BL21(DE3) bearing an ice-nucleation-protein anchor fused to repeated silaffin-derived R5 segments associated with titanium-containing precursor deposition and shaped the subsequently calcined product. Microscopy and diffraction support rod-shaped aggregates of anatase nanocrystals after heat treatment. The microbial contribution is an engineered biomass template and, under argon, a carbon source. The 600 degrees C crystallization stage is abiotic. This coupled process is not demonstrated growth on titanium, metabolic titanium reduction or isolated-metal recovery.

Experimental Context & Analytical Limits:
The original supplement identifies BL21(DE3) and pET(INP-nR5) constructs with one, three or five R5 repeats; NCBITaxon:562 maps the species only. Its synthesis section uses cell pellets in 10 mL Tris-buffered saline, specified as 50 mM Tris-HCl at pH 7.0 and 300 mM NaCl, with 2 mL titanium(IV) bis(ammonium lactato) dihydroxide solution. The precursor stock concentration and pellet biomass loading are not supplied there. This is a synthetic reagent feed, not a mineral leachate. The mixture was incubated at 37 degrees C for 24 h and then at 80 degrees C for 24 h, centrifuged, water-washed and freeze-dried. Products were heated at 600 degrees C for 4 h in air or argon, with respective heating rates of 10 and 4 degrees C/min. The supplement's separate membrane-fraction preparation is for protein analysis and is not substituted for the cell-pellet synthesis procedure. Viability during mineralization or after heating was not measured in the reported assays. The buffered starting pH is not a measured reaction pH trajectory. These are laboratory material-synthesis and coin-cell experiments, not industrial deployment.
Curated Evidence Points:
Main Figures 1-4 and Supporting Figures S2, S4-S8 support cell-associated precursor deposition, retention of a rod-like template after heating, and an anatase-assigned crystalline product characterized by XRD, electron diffraction and lattice imaging. The five-repeat air-treated product is described as approximately 5 nm particles, while Figure 3 labels its size 5.8 plus or minus 0.8 nm. Those descriptions are not treated as identical measurements or a production yield. Argon-treated material additionally contains carbon observed by microscopy, elemental mapping and Raman analysis; it is an anatase-carbon composite, not an assertion of pure recovered titanium.
At 37 degrees C, Figure 1b electron diffraction and Figure S2g support largely amorphous precursor rather than established crystalline anatase. The authors interpret a weak broad peak near 26 degrees in S2h after the 80 degrees C stage as anatase nuclei; that low-crystallinity assignment is weaker than the post-calcination diffraction evidence. The main text on page 6332 cites powder reference 21-1271, whereas Figure 2e and Supporting Figure S6 both label 21-1272. No reference-card identifier is independently adopted here. The phase assignment rests on the source's combined reported characterization, not on nominal TiO2 composition alone.
INP-only cells provide a relevant protein-display comparator: Figure S2 shows smoother surfaces than the five-repeat arm, and S4b shows aggregated particles with loss of the rod shape after heating. Thus the control supports a morphology effect; it does not show that titanium-containing solids can form only with R5 or only through microbial metabolism. The one-, three- and five-repeat comparisons further associate repeat number with particle size. No matched cell-free precursor control, live-versus-killed comparison, titanium mass balance or quantitative isolated-product yield is reported for this synthesis. Biological replicate counts and the statistical basis of Figure 3's size uncertainties are not specified.
Context_only Source: ping2016
The electrostatic binding, hydrogen-bond catalysis and protein confinement steps in Figures 1d, 3d and 5 are proposed molecular explanations, not direct measurements of each catalytic intermediate or proof of a specific active enzyme pathway. Figure S1 documents membrane-protein bands without a viability assay. Subsequent lithium-battery capacities, fitted diffusion coefficients and modeled carbon coverage concern material performance; they are not titanium extraction or recovery endpoints and are not imported as such.

Sources & References

  1. ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026. Anatase row on PDF page 10: TiO2, A, 1962 s.p., France; definitions on page 1 and distribution terms on page 2.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-12)
  2. ping2016: Ping H, Xie H, Xiang M and colleagues (2016). Confined-space synthesis of nanostructured anatase, directed by genetically engineered living organisms for lithium-ion batteries. Chemical Science 7:6330-6336. DOI 10.1039/C6SC02311H. Complete seven-page primary article, Figures 1-7, and original fourteen-page Supporting Information, especially experimental section pages 2-3 and Figures S1-S9; Tables S1-S2 are battery context.
    https://doi.org/10.1039/C6SC02311H (accessed 2026-10-12)
  3. ncbi_ecoli: NCBI Taxonomy 562, Escherichia coli, species. The species mapping does not independently authenticate the engineered BL21(DE3) stocks or recombinant constructs used by Ping and colleagues.
    https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=562 (accessed 2026-10-12)

Curation History

Timestamp Curator Action Summary
2026-10-12T06:48:07Z codex (GPT-6; codex) CREATE Created the distinct anatase mineral with a qualified engineered-biomass template and abiotic thermal-crystallization process; retained phase, control, biomass and yield limitations.
2026-10-12T07:00:49Z codex (GPT-6; codex) EDIT Corrected issue 156 and independent finding F1: page 6332 prose cites 21-1271, while Figure 2e and Supporting Figure S6 both label 21-1272; retained the source discrepancy and all other scientific claims.

Record source: data/records/anatase.yaml