Chromium-tanned leather shavings secondary resource
Chromium-bearing collagenous shavings generated during leather manufacture after chrome tanning, represented here by wet-blue tannery waste from Poland. This processing residue is distinct from tannery wastewater-treatment sludge, tanning liquors, elemental chromium and purified collagen. The accepted laboratory evidence concerns yeast-associated matrix bioconversion and chromium partitioning, not an isolated chromium product or industrial deployment. Constituent criticality is not inherited.
Microbial & Biochemical Mechanisms (1)
Yeast-associated matrix bioconversion and chromium partitioning
other
Microbial
Associated Organisms:
Yarrowia lipolytica (NCBITaxon:4952)
Living Yarrowia lipolytica IPS21 cultures were associated with proteolytic activity, increased soluble amino acids, changing pH and altered total-chromium concentrations in operational liquid and combined biomass/residue fractions. These observations support conditional bioconversion of a chromium-bearing waste matrix. They do not establish purified chromium recovery, a closed chromium extraction yield, intracellular chromium exclusion or a demonstrated redox mechanism.
Experimental Context & Analytical Limits:
Wieczorek et al. obtained wet-blue chrome-tanned shavings from a Polish tannery at source-reported 51°29′37.8″N, 21°08′43.1″E. Reported moisture was 15% and aqueous-extract pH 3.09; the listed 4.4 ± 0.2% chromium(III) oxide, ash and nitrogen values are attributed to earlier literature rather than clearly documented lot-specific characterization. Particle sizes were reported as 1–5 mm. Source-designated IPS21 came from the institute collection, originally isolated from contaminated soil near the former BORUTA dye factory. Laboratory assays used 100 mL flasks with 40 mL sterile modified YPG medium and 0.1–4% (wt/wt) shavings, with 0.4 or 0.8 mL inoculum, 30°C, 190 rpm and 48 h. Initial pH was set to 7.07 before autoclaving at 121°C for 20 min. Yeast extract supplies nutrients independently of the shavings. The abstract gives 15 g/L yeast extract and 5 g/L NaCl, whereas the stock-medium method gives 2.5 g/L NaCl and agar; the final liquid recipe is not fully reconciled. The printed inoculum OD600 token is 1,000, with no independently verified viable-cell count. Yeast-only, medium-only and uninoculated shavings comparisons appear for the relevant endpoints; comparisons are not pH-matched. Total-Cr experiments concern 0.1% and 1% feeds, not the 4% arm. Reported endpoint summaries use n=3. No industrial treatment trial is established.
Wieczorek et al. obtained wet-blue chrome-tanned shavings from a Polish tannery at source-reported 51°29′37.8″N, 21°08′43.1″E. Reported moisture was 15% and aqueous-extract pH 3.09; the listed 4.4 ± 0.2% chromium(III) oxide, ash and nitrogen values are attributed to earlier literature rather than clearly documented lot-specific characterization. Particle sizes were reported as 1–5 mm. Source-designated IPS21 came from the institute collection, originally isolated from contaminated soil near the former BORUTA dye factory. Laboratory assays used 100 mL flasks with 40 mL sterile modified YPG medium and 0.1–4% (wt/wt) shavings, with 0.4 or 0.8 mL inoculum, 30°C, 190 rpm and 48 h. Initial pH was set to 7.07 before autoclaving at 121°C for 20 min. Yeast extract supplies nutrients independently of the shavings. The abstract gives 15 g/L yeast extract and 5 g/L NaCl, whereas the stock-medium method gives 2.5 g/L NaCl and agar; the final liquid recipe is not fully reconciled. The printed inoculum OD600 token is 1,000, with no independently verified viable-cell count. Yeast-only, medium-only and uninoculated shavings comparisons appear for the relevant endpoints; comparisons are not pH-matched. Total-Cr experiments concern 0.1% and 1% feeds, not the 4% arm. Reported endpoint summaries use n=3. No industrial treatment trial is established.
Curated Evidence Points:
Support
Source:
wieczorek2023
Methods Biological material, Waste material, Biotransformation process and Determination of the total chromium; Tables 1–2 and Figures 1–4 support laboratory culture-associated transformation. Protease activity and amino-acid concentrations increased in selected culture/feed arms; uninoculated shavings acidified the medium while corresponding yeast treatments became more alkaline. Figure 4 shows a larger supernatant total-Cr concentration and a smaller combined solid-residue contribution for the 1% yeast treatment than for the 1% uninoculated treatment. These operational endpoints support conditional redistribution, not an independently quantified isolated product.
Partial
Source:
wieczorek2023
Figure 4 stacks quantities labelled total chromium in g/kg for liquid and solid fractions. Methods digest 0.1 g or 0.1 mL and dilute to 25 mL but do not clearly define a common mass basis, fraction masses, liquid density or complete starting/ending inventory. Stacking these concentrations cannot establish an elemental mass balance or recovery fraction. The Results assign 10.31 g/kg to the 0.1% yeast sample, whereas the plotted value near 10 belongs to the 1% uninoculated supernatant. No exact extraction percentage or corrected numerical assignment is adopted.
Partial
Source:
wieczorek2023
The measured solid residue explicitly combines biomass and remaining shavings. The discussion infers little intracellular chromium, but the assay does not separate intracellular uptake from surface sorption, retained feed or abiotic precipitation. Yeast-associated pH shifts also change chromium chemistry; no pH-matched sterile or enzyme-inactivated comparison establishes the contribution of proteases versus alkalinization or other culture products. Proposed chromium hydroxide/oxide chemistry is not direct phase identification.
Partial
Source:
wieczorek2023
Supplemental file 2 reports Cr(VI) as not detected in medium, 0.1% and 1% shavings supernatants and corresponding residues, with stated bounds ≤1 mg/L for liquids and ≤1 mg/kg for residues. These censored results are retained as nondetections, not zeros, proof that oxidation never occurred, or a complete chromium-speciation balance. They do not extend to the 4% arm.
Partial
Source:
wieczorek2023
Table 1 lists larger 48 h source-labelled degradation rates at 1% shavings than at 4%, contrary to the Results/abstract narrative favoring 4%. Methods say this rate was calculated from biomass concentration but give no explicit equation separating yeast from residual feed; it is not a chromium yield or a demonstrated collagen mass balance. Added yeast extract and the yeast-only amino-acid response prevent attributing all soluble products to the shavings. No universal optimum is accepted.
Context_only
Source:
wieczorek2023
Supplemental files 3a and 3b contain sequences for laboratory samples 1304–1306 and a species report assigning sample C/1306 to Yarrowia lipolytica. They do not supply a public IPS21 accession or an explicit sample-number-to-IPS21 crosswalk. The identification report is dated October 2021, while main text describes sequencing in 2022; February 2022 email printouts accompany the sequences. IPS21 remains the paper-reported strain designation, distinct from an independently verified culture accession.
Context_only
Source:
wieczorek2023
Figure 5 and the separate short plant assay evaluate diluted supernatants, while supplemental file 5 depicts plate growth around shavings. Neither establishes comprehensive detoxification, safe fertilizer use, industrial deployment or recovered chromium product quality. Those conclusions are not adopted.
Context_only
Source:
ncbi4952
The current official species entry resolves Yarrowia lipolytica and taxon 4952. It does not validate the experimental stock, sequence provenance, matrix-specific mechanism or source-level strain identity.
Sources & References
-
wieczorek2023: Dorota Wieczorek, Dorota Gendaszewska, Katarzyna Miśkiewicz, Anna Słubik and Katarzyna Ławińska (2023). Biotransformation of protein-rich waste by Yarrowia lipolytica IPS21 to high-value products—amino acid supernatants. Microbiology Spectrum 11(5):e02749-23. DOI 10.1128/spectrum.02749-23; PMID 37707427; PMC10581069. Complete original JATS/HTML, Tables 1–2, Figures 1–5 and all five supplemental PDFs inspected; the nominal local main-PDF download was HTML and is not evidence.
https://doi.org/10.1128/spectrum.02749-23 (accessed 2026-10-15) -
ncbi4952: NCBI Taxonomy 4952: Yarrowia lipolytica, species. Current official taxonomy XML verifies the species label, not the identity or performance of the experimental IPS21 stock.
https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=4952&mode=Info (accessed 2026-10-15)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-15T05:08:31.055559Z |
Codex (GPT-6; codex) | CREATE | Created a distinct leather-shavings secondary-resource record from the complete Wieczorek2023 original and supplements, retaining conditional yeast-associated matrix conversion, chromium partitioning, censored Cr(VI), source discrepancies and control limits without a recovery-yield or deployment claim. |
Record source: data/records/chromium-tanned-leather-shavings.yaml