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Published on: October 15, 2015
Characterization of sediment bacteria involved in selenium reduction
Tariq Siddique1, Yiqiang Zhang, Benedict C Okeke
1Department of Environmental Sciences, University of California, Riverside, CA 92521-0424, USA.
Bioresource Technology
|December 6, 2005
Summary
Bacterial selenium reduction removes toxic selenium from agricultural water. Adding organic carbon stimulates these microbes, showing potential for bioremediation in contaminated environments.
Area of Science:
- Environmental Microbiology
- Biogeochemistry
- Bioremediation
Background:
- Bacterial reduction of selenium (Se) oxyanions to elemental Se is a key process in removing Se from agricultural drainage.
- This process impacts Se deposition in sediments and influences its biogeochemical cycling.
- Understanding Se-reducing bacteria in contaminated environments is crucial for managing Se pollution.
Purpose of the Study:
- To characterize selenium-reducing bacterial populations in Lost Hills evaporation pond sediment.
- To investigate the response of these bacteria to amendments of selenium (VI) and organic carbon.
- To explore the potential application of isolated bacterial strains for selenium removal from high-salt drainage water.
Main Methods:
- Incubation of sediment slurries with selenium (VI) and organic carbon amendments.
- Monitoring of redox potential (Eh) and dissolved selenium (VI) concentrations.
- Isolation and identification of Se-reducing bacteria using 16S rDNA sequencing.
Main Results:
- Organic carbon amendments led to significant Se(VI) removal from the dissolved phase and a decrease in redox potential.
- Se(VI) concentrations dropped from 2137 to 79 microg L-1 within 9 days in a 5% soil slurry.
- Nine Se(VI)-reducing and fourteen Se(IV)-reducing bacterial strains were isolated, with Bacillus strains being dominant. Halomonas pacifica and Staphylococcus warneri were identified as Se(IV)-reducers.
Conclusions:
- Indigenous bacteria play a significant role in selenium biogeochemical cycling.
- Stimulation of Se-reducing bacteria by organic carbon amendments is effective for selenium removal.
- Bacterial strains from Lost Hills evaporation pond sediment show promise for bioremediating selenium-contaminated, high-salt drainage water.
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