Dataset Information

Hexavalent chromium release over time from a pyrolyzed Cr-bearing tannery sludge.

ABSTRACT: Pyrolysis in an inert atmosphere is a widely applied route to convert tannery wastes into reusable materials. In the present study, the Cr(III) conversion into the toxic hexavalent form in the pyrolyzed tannery waste referred to as KEU was investigated. Ageing experiments and leaching tests demonstrated that the Cr(III)-Cr(VI) inter-conversion occurs in the presence of air at ambient temperature, enhanced by wet environmental conditions. Microstructural analysis revealed that the Cr-primary mineral assemblage formed during pyrolysis (Cr-bearing srebrodolskite and Cr-magnetite spinel) destabilized upon spray water cooling in the last stage of the process. In the evolution from the higher to the lower temperature mineralogy, Cr is incorporated into newly formed CrOOH flakes which likely react in air forming extractable Cr(VI) species. This property transforms KEU from an inert waste to a hazardous material when exposed to ordinary ambient conditions.

SUBMITTER: Ghezzi L

PROVIDER: S-EPMC10539330 | biostudies-literature | 2023 Sep

REPOSITORIES: biostudies-literature

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Hexavalent chromium release over time from a pyrolyzed Cr-bearing tannery sludge.

Ghezzi Lisa L Mugnaioli Enrico E Perchiazzi Natale N Duce Celia C Pelosi Chiara C Zamponi Erika E Pollastri Simone S Campanella Beatrice B Onor Massimo M Abdellatief Mahmoud M Franceschini Fabrizio F Petrini Riccardo R

Scientific reports 20230928 1

Pyrolysis in an inert atmosphere is a widely applied route to convert tannery wastes into reusable materials. In the present study, the Cr(III) conversion into the toxic hexavalent form in the pyrolyzed tannery waste referred to as KEU was investigated. Ageing experiments and leaching tests demonstrated that the Cr(III)-Cr(VI) inter-conversion occurs in the presence of air at ambient temperature, enhanced by wet environmental conditions. Microstructural analysis revealed that the Cr-primary mine ...[more]

PMID: 37770570

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Project description:BackgroundEnvironmental stress induced genetic polymorphisms have been suggested to arbitrate functional modifications influencing adaptations in microbes. The relationship between the genetic processes and concomitant functional adaptation can now be investigated at a genomic scale with the help of next generation sequencing (NGS) technologies. Using a NGS approach we identified genetic variations putatively underlying chromium tolerance in a strain of Aspergillus flavus isolated from a tannery sludge. Correlation of nsSNPs in the candidate genes (n = 493) were investigated for their influence on protein structure and possible function. Whole genome sequencing of chromium tolerant A. flavus strain (TERIBR1) was done (Illumina HiSeq2000). The alignment of quality trimmed data of TERIBR1 with reference NRRL3357 (accession number EQ963472) strain was performed using Bowtie2 version 2.2.8. SNP with a minimum read depth of 5 and not in vicinity (10 bp) of INDEL were filtered. Candidate genes conferring chromium resistance were selected and SNPs were identified. Protein structure modeling and interpretation for protein-ligand (CrO4- 2) docking for selected proteins harbouring non-synonymous substitutions were done using Phyre2 and PatchDock programs.ResultsHigh rate of nsSNPs (approximately 11/kb) occurred in selected candidate genes for chromium tolerance. Of the 16 candidate genes selected for studying effect of nsSNPs on protein structure and protein-ligand interaction, four proteins belonging to the Major Facilitator Superfamily (MFS) and recG protein families showed significant interaction with chromium ion only in the chromium tolerant A. flavus strain TERIBR1.ConclusionsPresence of nsSNPs and subsequent amino-acid alterations evidently influenced the 3D structures of the candidate proteins, which could have led to improved interaction with (CrO4- 2) ion. Such structural modifications might have enhanced chromium efflux efficiency of A. flavus (TERIBR1) and thereby offered the adaptation benefits in counteracting chromate stress. Our findings are of fundamental importance to the field of heavy-metal bio-remediation.

Dataset Information

Hexavalent chromium release over time from a pyrolyzed Cr-bearing tannery sludge.

Publications

Hexavalent chromium release over time from a pyrolyzed Cr-bearing tannery sludge.

Similar Datasets

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