Construction and evaluation of a metal ion biosensor
1Howard P. Isermann Department of Chemical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180-3590, USA.
Biotechnology and Bioengineering
|October 1, 1993
Summary
Genetically engineered Escherichia coli bacteria serve as sensitive bioluminescent sensors for mercury detection. Optimized conditions enhance light output and rapid response times for environmental monitoring.
Area of Science:
- Microbiology
- Environmental Science
- Biotechnology
Background:
- Mercury contamination poses significant environmental and health risks.
- Development of rapid and sensitive detection methods for mercury is crucial.
- Microbial biosensors offer a promising approach for environmental monitoring.
Purpose of the Study:
- To engineer and evaluate a microbial biosensor for mercury detection using genetically modified Escherichia coli.
- To optimize parameters influencing the performance of the mercury biosensor.
- To assess the sensitivity, specificity, and response time of the biosensor.
Main Methods:
- Genetic engineering of Escherichia coli with a mercury(II)-sensitive promoter and lux genes.
- Optimization of cell concentration, temperature, mixing speed, and aeration.
- Evaluation of sensor performance in a small vessel and a miniature probe.
- Determination of sensitivity range, specificity, and response time.
Main Results:
- Optimized conditions (mid-exponential phase, 28°C, 1x10^9 cells/mL, high mixing, 2 vvm aeration) maximized light intensity and induction speed.
- The biosensor detected mercuric ions in the range of 20 nM to 4 µM (4-800 ppb) with a response time of approximately 1 hour.
- High specificity for mercury was observed, with similar sensitivity to organic and inorganic forms.
- A miniature probe demonstrated sensitivity from 10 nM to 4 µM with aeration.
Conclusions:
- Genetically engineered E. coli provides a sensitive and specific microbial biosensor for mercury detection.
- Optimized environmental parameters significantly enhance biosensor performance.
- The developed biosensor is suitable for environmental monitoring applications due to its sensitivity, specificity, and cost-effectiveness.
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