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Binding of Dissolved Strontium by Micrococcus luteus.
B D Faison1, C A Cancel, S N Lewis
1Chemical Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6194.
Applied and Environmental Microbiology
|December 1, 1990
Summary
Micrococcus luteus cells efficiently remove strontium (Sr) from water. This non-metabolic process involves Sr binding to the cell envelope, suggesting potential for bioremediation applications.
Area of Science:
- Microbiology
- Environmental Science
- Bioremediation
Background:
- Strontium (Sr) is a radioactive element with environmental implications.
- Microbial biosorption offers a potential method for heavy metal removal from aqueous solutions.
Purpose of the Study:
- To investigate the capacity and characteristics of strontium (Sr) removal by resting Micrococcus luteus cells.
- To elucidate the mechanisms and location of Sr binding on the bacterial cell surface.
Main Methods:
- Exposure of resting Micrococcus luteus cells to dilute strontium chloride (SrCl2) solutions.
- Analysis of Sr binding capacity, kinetics, and influence of various cations and chemical treatments.
- Localization of Sr binding activity on the bacterial cell envelope.
Main Results:
- Micrococcus luteus achieved high Sr loadings (25 mg Sr/g dry weight) from 50 ppm Sr solutions.
- Sr binding was rapid, reversible, and did not require metabolic activity or nutrients.
- Binding was inhibited by polyvalent cations and preferentially involved Ca and Sr; bound Sr was displaced by divalent ions or H+.
Conclusions:
- Sr binding by Micrococcus luteus is a reversible equilibrium process.
- Ion exchange via acidic cell surface components and potential intracellular uptake contribute to Sr binding.
- The cell envelope is the primary site for Sr binding activity.