Titanogypsum secondary resource
Heterogeneous solid residue described by the source as titanium gypsum or titanogypsum from titanium-dioxide production. The curated feed is a real Taizhou, Jiangsu plant waste, distinct from natural gypsum, titanium dioxide, phosphogypsum from phosphoric-acid manufacture and a purified calcium-sulfate product. Its unusual reported bulk composition and mixed phase assignments are retained rather than imposing pure-gypsum stoichiometry. Laboratory culture-associated redistribution of fluorine does not establish recovery of a fluorine product, a safe agricultural amendment or industrial deployment. No constituent-element criticality is inherited.
Microbial & Biochemical Mechanisms (1)
Yeast-associated fluoride redistribution in titanogypsum slurries
biosorption
Microbial
Associated Organisms:
Rhodotorula mucilaginosa (NCBITaxon:5537)
Living red-yeast cultures were associated with lower filtered aqueous fluoride and fluoride detected in an extracted extracellular-polymer fraction after contact with titanogypsum. Sorption and concurrent mineral partitioning are proposed explanations; the experiment does not isolate a unique binding pathway or demonstrate enhanced dissolved-fluoride extraction from this feed. Broader phosphogypsum responses in the same article are not transferred to titanogypsum.
Experimental Context & Analytical Limits:
Chen et al. report orchard-rhizosphere isolate CGMCC No.16597, activated in potato dextrose broth at 28 degrees C and 180 rpm for 48 h. No sequence accession is supplied to authenticate the experimental culture. Waste was ground, sieved through source-designated 500 mesh (less than 25 micrometres), and dried at 80 degrees C for 24 h. Laboratory assays used 5 or 10 g powder in 150 mL YPD medium in 250 mL flasks, plus 2 mL culture after sterilization. The reported medium contained 20 g peptone, 10 g glucose and 20 g yeast powder per litre, initially pH 7.0-7.4. Incubation was five days at 36 degrees C, in darkness, at 180 rpm, with three replicates. Controls included uninoculated waste-medium arms, medium alone and yeast without waste; no pH-matched sterile or killed-cell comparator was reported. After centrifugation, liquid was filtered at 0.22 micrometres and diluted fivefold for ion chromatography and ICP-OES. A separate 60 mL liquid fraction underwent centrifugation, ethanol precipitation and dialysis before the extracellular-polymer assay.
Chen et al. report orchard-rhizosphere isolate CGMCC No.16597, activated in potato dextrose broth at 28 degrees C and 180 rpm for 48 h. No sequence accession is supplied to authenticate the experimental culture. Waste was ground, sieved through source-designated 500 mesh (less than 25 micrometres), and dried at 80 degrees C for 24 h. Laboratory assays used 5 or 10 g powder in 150 mL YPD medium in 250 mL flasks, plus 2 mL culture after sterilization. The reported medium contained 20 g peptone, 10 g glucose and 20 g yeast powder per litre, initially pH 7.0-7.4. Incubation was five days at 36 degrees C, in darkness, at 180 rpm, with three replicates. Controls included uninoculated waste-medium arms, medium alone and yeast without waste; no pH-matched sterile or killed-cell comparator was reported. After centrifugation, liquid was filtered at 0.22 micrometres and diluted fivefold for ion chromatography and ICP-OES. A separate 60 mL liquid fraction underwent centrifugation, ethanol precipitation and dialysis before the extracellular-polymer assay.
Curated Evidence Points:
Support
Source:
chen2021
Figure 2D and the Results subsection on element release show lower aqueous fluoride in both TG-Rho arms than their uninoculated TG comparators. Figure 7D detects fluoride in the ethanol-precipitated, dialyzed polymer-associated fractions from TG5-Rho and TG10-Rho. Figure 5D shows source-interpreted yeast cells at the TG surface. These are culture-associated partitioning observations, not an isolated-fluorine product or a mass-balanced recovery percentage.
Partial
Source:
chen2021
Figure 2B reports no significant phosphorus change between TG and matched TG-Rho arms; Figure 2C shows differing final pH. TG images lack the conspicuous extracellular material seen with phosphogypsum. The authors infer inhibition by fluoride, but do not isolate fluoride toxicity from other feed properties. No polymer-free matched reaction, quantitative cell viability assay or causal acid/enzyme intervention resolves how much of the fluoride response is sorption, precipitation or changed dissolution. Soluble Pb, Cd, Zn and Cu were reported below 0.05 mg/L in the tested solutions, not absent from the feed.
Partial
Source:
chen2021
Figure 3B contains the TG XRF comparison, although the adjacent prose assigns TG to Figure 3A. The reported reduction in solid fluorine proportion is a compositional comparison after preparation involving 600 degrees C pyrolysis, not an overall recovery yield. Table 1 reports unusually low sulfur relative to calcium in this source-labelled titanium gypsum; no pure gypsum composition is inferred. Figure 4B assigns overlapping peaks in mixed solids to calcium salts including fluorophosphate, with phosphate-related signals also marked in uninoculated material. No isolated phase, quantitative phase balance or direct demonstration of exclusive microbial mineral formation is provided. Fluoride in a separated polymer fraction does not itself measure an adsorption capacity per mass of polymer.
Partial
Source:
chen2021
The abstract's g/mL loading statements conflict with Methods specifying 5 or 10 g in 150 mL. Some comparisons repeat the same sample label on both sides, including TG10-Rho in the polymer-fluoride discussion. Figure-defined arms and the explicit flask recipe are retained; source percentages with unresolved denominators are not adopted. No soil, plant, toxicological or field-deployment experiment establishes the proposed safety or reuse claims.
Context_only
Source:
chen2021_supplement
Figure S1 labels phosphorus measurements in deionized water, rather than the YPD culture medium used for the main experiment; its limited protocol does not resolve the culture mechanism or a phosphorus mass balance. Figure S2 images phosphogypsum and cannot establish titanogypsum fragmentation or polymer encapsulation.
Sources & References
-
chen2021: Chen, Lu, Zhang, Min and Huo (2021). Red Yeast Improves the Potential Safe Utilization of Solid Waste (Phosphogypsum and Titanogypsum) Through Bioleaching. Frontiers in Bioengineering and Biotechnology 9:777957. DOI 10.3389/fbioe.2021.777957; Materials and Methods, Results and Discussion, Table 1 and Figures 1-7, especially the TG arms of Figures 2, 3B, 4B, 5C-D, 6 and 7B,D. Published 31 December 2021.
https://doi.org/10.3389/fbioe.2021.777957 (accessed 2026-10-15) -
chen2021_supplement: Supplementary DataSheet1.docx associated with Chen et al. (2021), DOI 10.3389/fbioe.2021.777957; Figures S1-S2. S1 labels the separate deionized-water phosphorus comparison; S2 concerns phosphogypsum, not titanogypsum. This supplement is the same study, not replication.
https://www.ebi.ac.uk/europepmc/webservices/rest/PMC8758580/supplementaryFiles (accessed 2026-10-15) -
ncbi_rhodotorula: NCBI Taxonomy 5537, Rhodotorula mucilaginosa, species. Species identity context only; not authentication of experimental CGMCC No.16597.
https://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=taxonomy&id=5537&retmode=xml (accessed 2026-10-15)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-15T01:20:30.521805+00:00 |
codex (GPT-6; codex) | CREATE | Created a distinct titanium-dioxide-production waste record retaining culture-associated fluoride partitioning, null phosphorus response and unresolved source composition and units. |
Record source: data/records/titanogypsum.yaml