Bobierrite mineral
Bobierrite is the hydrated magnesium phosphate mineral species Mg3(PO4)2(H2O)8. The September 2026 IMA list gives grandfathered status and original-description year 1868, not an approval identifier. It is distinct from the other mineral species barićite, from elemental magnesium or phosphorus, and from mixed phosphate products. The studies below assign bobierrite to recovered culture precipitates; neither proves a purified product or industrial recovery. Constituent criticality is not inherited.
Microbial & Biochemical Mechanisms (2)
Bobierrite-assigned aggregates from a soil bacterial isolate
biomineralization
Microbial
A soil isolate identified phenotypically as Acinetobacter sp. produced extracellular crystal aggregates assigned to bobierrite in both solid and liquid B-17 medium. The assignment is supported by powder diffraction, infrared spectra and chemical analysis, with explicit impurity and control-reporting limits.
Experimental Context & Analytical Limits:
Rivadeneyra et al. screened 96 soil isolates previously capable of calcium carbonate formation. One Acinetobacter sp. isolate produced the target aggregates, whereas 20 others reportedly formed struvite. No deposited strain accession or species identification is provided. B-17 contained, per litre, 4 g yeast extract, 2.4 g magnesium acetate (hydration unspecified), and 0.5 g potassium nitrate; solid medium additionally contained 1.6% Bacto-Agar. Initial pH was adjusted to 8 with 0.1 M NaOH before sterilization at 121 degrees C for 20 min. No separate inorganic phosphate addition is listed. Inoculated cultures were incubated aerobically at 27 degrees C and observed for up to 35 days. The experiments were in triplicate and repeated three times, reported as nine experiments for each medium. Uninoculated and autoclaved-cell controls were included, but their outcomes are not explicitly presented in the five-page article.
Rivadeneyra et al. screened 96 soil isolates previously capable of calcium carbonate formation. One Acinetobacter sp. isolate produced the target aggregates, whereas 20 others reportedly formed struvite. No deposited strain accession or species identification is provided. B-17 contained, per litre, 4 g yeast extract, 2.4 g magnesium acetate (hydration unspecified), and 0.5 g potassium nitrate; solid medium additionally contained 1.6% Bacto-Agar. Initial pH was adjusted to 8 with 0.1 M NaOH before sterilization at 121 degrees C for 20 min. No separate inorganic phosphate addition is listed. Inoculated cultures were incubated aerobically at 27 degrees C and observed for up to 35 days. The experiments were in triplicate and repeated three times, reported as nine experiments for each medium. Uninoculated and autoclaved-cell controls were included, but their outcomes are not explicitly presented in the five-page article.
Curated Evidence Points:
Partial
Source:
rivadeneyra_1987
Pages 444-445 and Figure 1 identify the recovered aggregates by XRD comparison to bobierrite; Figures 2-3 provide infrared spectra and SEM. The authors report the same recovered crystal characteristics from solid and liquid media, with aggregates in every trial of this isolate. They explicitly identify unmatched diffraction peaks and intensity differences consistent with impurities. No quantitative phase refinement or pure-product yield is supplied.
Partial
Source:
rivadeneyra_1987
Crystal separation and purification are referred to a 1983 method without reproducing the procedure; that original method was not inspected here, so handling effects cannot be excluded. No wet-crystal diffraction, final culture pH, cell dose, solution phosphate balance or explicit control outcome is reported. The observation supports a historical culture-associated phase assignment, not a demonstrated biochemical pathway or a quantified enhancement over abiotic precipitation. Soil origin does not establish in situ soil mineral formation.
Bobierrite-assigned spherulites recovered from nutrient agar cultures
biomineralization
Microbial
A separate study reports bobierrite among magnesium-phosphate spherulites recovered from bacterial cultures on artificial nutrient agar. The accepted claim is the source-assigned recovered phase associated with live cultures; in-culture hydration state and an isolate-specific bobierrite yield remain unresolved.
Experimental Context & Analytical Limits:
Twelve dominant colony types were isolated and purified from a bench domestic-wastewater biofilm reactor, then separately surface-inoculated on SS1 and SS2 agar at 25 degrees C for 30 days under aerobic conditions. Both media contained 10 g/L yeast extract, 5 g/L protease peptone, 1 g/L glucose and 18 g/L agar, initial pH 7.2 with KOH, autoclaved at 112 degrees C for 20 min. SS1 additionally contained 4 g/L MgSO4.7H2O and 2.5 g/L K2HPO4; SS2 contained 8 g/L magnesium acetate of unspecified hydration and no separately listed inorganic phosphate. Table 3 assigns struvite plus spherulites to isolates 1, 2, 5, 7, 9 and 12 in the solid media; it does not map bobierrite versus barićite individually to each isolate. The experiments were reported as performed twice. Spherulites were recovered by dissolving agar pieces in boiling water, washed in distilled water and air-dried at 37 degrees C before powder XRD and SEM-EDX.
Twelve dominant colony types were isolated and purified from a bench domestic-wastewater biofilm reactor, then separately surface-inoculated on SS1 and SS2 agar at 25 degrees C for 30 days under aerobic conditions. Both media contained 10 g/L yeast extract, 5 g/L protease peptone, 1 g/L glucose and 18 g/L agar, initial pH 7.2 with KOH, autoclaved at 112 degrees C for 20 min. SS1 additionally contained 4 g/L MgSO4.7H2O and 2.5 g/L K2HPO4; SS2 contained 8 g/L magnesium acetate of unspecified hydration and no separately listed inorganic phosphate. Table 3 assigns struvite plus spherulites to isolates 1, 2, 5, 7, 9 and 12 in the solid media; it does not map bobierrite versus barićite individually to each isolate. The experiments were reported as performed twice. Spherulites were recovered by dissolving agar pieces in boiling water, washed in distilled water and air-dried at 37 degrees C before powder XRD and SEM-EDX.
Curated Evidence Points:
Partial
Source:
rivadeneyra_2014
Results pages 3697-3699, Table 3 and Figure 4 assign bobierrite and baricite to spherulite products. Figure 4 displays an XRD intensity map with SP1/SP2 labels rather than per-isolate quantitative phase fits. Figure 5 names bobierrite and Mg3(PO4)2.2H2O, conflicting with the adjacent baricite octahydrate assignment. EDX does not establish hydration state or distinguish these polymorphs. Unchanged optical morphology after boiling-water recovery does not establish unchanged crystal phase; no specific heat-induced transformation is inferred.
Partial
Source:
rivadeneyra_2014
Uninoculated and autoclaved dead-cell controls reportedly lacked crystals. Wastewater medium supported growth but no crystals at 30 days, and liquid SS1/SS2 counterparts produced struvite without reported spherulites. These are medium-dependent observations, not evidence of universal mineral production. Liquid Methods describes biofilm suspensions whereas Table 3 presents strain rows; that ambiguity does not justify assigning liquid phase outcomes to authenticated isolates.
Partial
Source:
rivadeneyra_2014
The 16S Methods describes approximately 650 nucleotides, Figure 3 approximately 200, and Table 2 identities cover 107-198 positions; strain 12 is 100% in Table 2 but 96% in prose. Sequence references identify comparison sequences rather than deposited experimental stocks. No exact organism CURIE or claim that every isolate forms bobierrite is assigned. A specific metabolic or surface pathway was not isolated, and the study lacks phase-specific mass balance, purified product testing and industrial deployment evidence. Reactor organic-load removal is not phosphate-mineral recovery.
Sources & References
-
ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026. Pages 1-2 definitions and terms; barićite page 20, bobierrite page 27. Retained official original re-inspected on 14 October 2026.
https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-14) -
rivadeneyra_1987: Rivadeneyra, Ramos-Cormenzana and García-Cervigón (1987). Formation of bobierrite (magnesium phosphate) crystal aggregates by Acinetobacter sp. Mineralogical Journal 13(7):443-447. DOI 10.2465/minerj.13.443. Complete five-page official J-STAGE scan visually inspected, including Figures 1-3.
https://doi.org/10.2465/minerj.13.443 (accessed 2026-10-14) -
rivadeneyra_2014: Rivadeneyra et al. (2014). Precipitation of Phosphate Minerals by Microorganisms Isolated from a Fixed-Biofilm Reactor Used for the Treatment of Domestic Wastewater. International Journal of Environmental Research and Public Health 11:3689-3704. DOI 10.3390/ijerph110403689; Sections 2.3-2.8, Tables 2-3 and Figures 4-5. Complete publisher PDF and PMC4025044 XML inspected.
https://doi.org/10.3390/ijerph110403689 (accessed 2026-10-14)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-14T08:16:55.696577+00:00 |
codex (GPT-6; codex) | CREATE | Created distinct phosphate mineral identity and qualified primary culture-phase assignments; retained processing, control, taxonomic and source consistency limits. |
Record source: data/records/bobierrite.yaml