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Sulfate-mediated Fe(III) mineral reduction accelerates arsenic mobilization by a Desulfovibrio strain isolated from paddy soil

  • 0Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
The Science of the Total Environment +

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September 29, 2024

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September 29, 2024

View abstract on PubMed

Summary

This summary is machine-generated.

Sulfate-reducing bacteria (SRB) isolated from paddy soil enhance arsenic mobilization by disrupting iron minerals. This process, driven by sulfide production, is critical for understanding arsenic cycling in contaminated environments.

Area Of Science

  • Environmental Microbiology
  • Biogeochemistry
  • Geochemistry

Background

  • Arsenic (As) biogeochemical cycling is closely linked with iron (Fe) and sulfur (S) cycles.
  • Fe(III)- and sulfate-reducing bacteria (SRB) are key players in these interconnected cycles.
  • Understanding microbial roles in As mobilization is crucial for contaminated site remediation.

Purpose Of The Study

  • To isolate and characterize anaerobic Fe(III)- and sulfate-reducing bacteria from arsenic-contaminated paddy soil.
  • To investigate the role of isolated bacteria in arsenic mobilization under sulfate-reducing conditions.
  • To elucidate the mechanisms by which these bacteria influence arsenic release.

Main Methods

  • Isolation of strictly anaerobic Fe(III)- and sulfate-reducing bacteria from paddy soil.
  • Identification of isolates using 16S rRNA gene sequence analysis.
  • Assessing arsenic mobilization under varying redox and sulfate conditions.
  • Analysis of microbial metabolic pathways involving iron and sulfur reduction.

Main Results

  • A strictly anaerobic Fe(III)- and sulfate-reducing bacterium, strain DS-1 (Desulfovibrio genus), was isolated.
  • Strain DS-1 utilizes ferrihydrite reduction for cellular energy and growth.
  • The presence of strain DS-1 significantly increased arsenic mobilization under anoxic sulfate-reducing conditions compared to sulfate-free conditions.
  • SRB-produced sulfide reacts with Fe(III) to form iron sulfide (FeS), disrupting Fe(III) minerals and enhancing As release.

Conclusions

  • Redox disequilibrium driven by sulfate-reducing bacteria critically influences arsenic mobilization.
  • Sulfide produced by SRB can lead to the disruption of iron minerals, facilitating arsenic release.
  • SRB-mediated arsenic mobilization may occur in rice rhizospheres, impacting arsenic bioavailability.

Keywords:

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