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Arsenic Detoxification Using Arsenic-Resistant Bacteria Bacillus cereus SP21 and Bacillus toyonensis SP23: A
Santhakumar Munusamy1, Lokesh Elumalai1, Gk Sri Ragavi1
1Department of Microbiology, Periyar University, Salem, India.
Journal of Basic Microbiology
|April 30, 2025
Summary
This study demonstrates microbial oxidation of toxic arsenite (As3+) to less harmful arsenate (As5+) using arsenic-resistant bacteria. Bacillus strains effectively removed arsenic from synthetic water, offering a sustainable detoxification method.
Area of Science:
- Environmental Microbiology
- Water Treatment Technologies
- Bioremediation
Background:
- Groundwater contamination by arsenic poses significant risks to human health and agriculture.
- Arsenic contamination in drinking water sources necessitates effective and sustainable remediation strategies.
- Arsenic-resistant bacteria (ARB) show potential for bioremediation of arsenic-polluted water.
Purpose of the Study:
- To investigate the microbial oxidation of arsenite (As3+) to arsenate (As5+) using selected arsenic-resistant bacterial strains.
- To optimize conditions for arsenic detoxification by Bacillus cereus (SP21) and Bacillus toyonensis (SP23).
- To evaluate the efficacy of immobilized bacterial cells in a lab-scale bioreactor for arsenic removal.
Main Methods:
- Screening of arsenic-resistant bacterial strains (Bacillus cereus SP21, Bacillus toyonensis SP23) for tolerance up to 100 ppm arsenic.
- Optimization of oxidation conditions, including carbon source (1.5% cellulose), temperature, and pH.
- Lab-scale column and bioreactor experiments utilizing immobilized bacterial cells for arsenic oxidation.
- Quantification of arsenite and arsenate using the molybdenum blue method with UV spectrophotometry.
Main Results:
- Bacillus cereus SP21 and Bacillus toyonensis SP23 demonstrated significant arsenic resistance.
- 1.5% cellulose was identified as the optimal carbon source for arsenic oxidation.
- Immobilized bacterial cells in a lab-scale bioreactor achieved maximum arsenic removal.
- Successful oxidation of arsenite (As3+) to arsenate (As5+) was confirmed.
Conclusions:
- The study successfully detoxified arsenic in synthetic water using microbial oxidation by Bacillus cereus SP21 and Bacillus toyonensis SP23.
- Immobilized arsenic-resistant bacteria offer a promising approach for arsenic remediation in contaminated water.
- This bioremediation strategy presents a sustainable solution for managing arsenic pollution in groundwater.
