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Removal of Arsenic Using a Cationic Polymer Gel Impregnated with Iron Hydroxide
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Arsenic Detoxification by Geobacter Species
Yan Dang1,2, David J F Walker1, Kaitlin E Vautour1
1Department of Microbiology, University of Massachusetts-Amherst, Amherst, Massachusetts, USA.
Applied and Environmental Microbiology
|December 13, 2016
Summary
Geobacter bacteria possess arsenic detoxification genes, crucial for understanding arsenic cycling in subsurface environments. This research reveals how these microbes impact arsenic mobility, aiding in remediation strategies.
Area of Science:
- Microbiology
- Environmental Science
- Biogeochemistry
Background:
- Geobacter species are key iron-reducing bacteria in anoxic subsurface environments.
- These bacteria significantly influence arsenic release from metal hydroxides, impacting drinking water quality.
- Understanding Geobacter's arsenic mechanisms is vital for global arsenic cycling insights.
Purpose of the Study:
- To investigate arsenic transformation and detoxification pathways in Geobacter species.
- To elucidate the genetic basis of arsenic resistance and respiration in Geobacter.
- To inform strategies for arsenic remediation and biosensor development.
Main Methods:
- Genomic analysis of 14 Geobacter species to identify arsenic-related genes (ars, arr, arsM operons).
- Gene knockout studies in Geobacter sulfurreducens, focusing on arsenic repressor (arsR1) and transporter (Acr3) genes.
- Phenotypic analysis of mutant strains under different arsenic conditions.
Main Results:
- All 14 Geobacter species possess the arsenic detoxification (ars) operon; some also have arsenic respiration (arr) and methylation (arsM) genes.
- ArsR1 in G. sulfurreducens regulates the ars operon, controlling arsenic efflux (Acr3) and reduction (ArsC) gene expression.
- Deletion of Acr3 prevented growth with both arsenate and arsenite, while arsC deletion impaired growth with arsenate only.
Conclusions:
- Geobacter plays a critical role in arsenic mobility in anoxic sediments.
- Specific genes like arsR1, Acr3, and ArsC are essential for Geobacter's arsenic detoxification and respiration.
- This study provides foundational knowledge for managing arsenic contamination in subsurface environments.
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