Related Experiment Video
Updated: Aug 14, 2026
09:27
Immobilization of Multi-biocatalysts in Alginate Beads for Cofactor Regeneration and Improved Reusability
Published on: April 22, 2016
Cyanide detoxification by recombinant bacterial rhodanese
Rita Cipollone1, Paolo Ascenzi, Emanuela Frangipani
1Dipartimento di Biologia, Università Roma Tre, Viale G. Marconi 446, 00146 Rome, Italy.
Chemosphere
|November 26, 2005
Summary
Engineered E. coli expressing Pseudomonas aeruginosa rhodanese (r-RhdA) detoxified cyanide to thiocyanate. This microbial rhodanese system shows potential for environmental remediation and increased bacterial resistance to cyanide pollution.
Area of Science:
- Biotechnology
- Environmental Science
- Microbiology
Background:
- Cyanide is a significant industrial pollutant due to its extreme toxicity.
- Rhodaneses (thiosulfate:cyanide sulfurtransferases) enzymatically convert cyanide to less toxic thiocyanate.
- Engineering microbial systems for cyanide detoxification is crucial for environmental remediation.
Purpose of the Study:
- To engineer a genetic system for high-level expression of recombinant Pseudomonas aeruginosa rhodanese (r-RhdA) in Escherichia coli.
- To evaluate the efficacy of engineered E. coli expressing r-RhdA in cyanide detoxification.
- To investigate the role and activity of microbial rhodaneses in cyanide transformation.
Main Methods:
- Inducible expression of the rhdA gene in E. coli using a T7-lacO promoter.
- Western blot analysis and enzymatic assays to determine r-RhdA localization and activity.
- Whole-cell and in vitro assays to measure cyanide conversion to thiocyanate and assess bacterial resistance.
Main Results:
- Active r-RhdA was successfully expressed, partitioning between the cytoplasm and periplasm.
- Thiosulfate accessibility limited the reaction rate in whole cells; permeabilization enhanced cyanide conversion.
- r-RhdA-expressing E. coli exhibited increased resistance to cyanide and released thiocyanate into the medium.
- Specific r-RhdA activity was higher in whole-cell assays compared to in vitro assays, suggesting enhanced enzyme stability.
Conclusions:
- Engineered E. coli cells demonstrate feasible cyanide detoxification under laboratory conditions.
- Microbial rhodaneses, like r-RhdA, can contribute to cyanide transformation in natural environments.
- This engineered system offers a potential biological solution for cyanide pollution management.
Related Concept Videos
01:19Phase II Reactions: Miscellaneous Conjugation Reactions
Phase II biotransformations are detoxification mechanisms that conjugate xenobiotics with endogenous substances, neutralizing their toxicity.
A key example involves the conjugation of cyanide ions, which impair cellular respiration and alter hemoglobin into non-oxygen-carrying cyanmethemoglobin. To neutralize this threat, a sulfur atom from thiosulphate is transferred to the cyanide ion, catalyzed by the enzyme rhodanese, resulting in an inactive compound called thiocyanate. The production of...
A key example involves the conjugation of cyanide ions, which impair cellular respiration and alter hemoglobin into non-oxygen-carrying cyanmethemoglobin. To neutralize this threat, a sulfur atom from thiosulphate is transferred to the cyanide ion, catalyzed by the enzyme rhodanese, resulting in an inactive compound called thiocyanate. The production of...
00:46Bioremediation
Bioremediation is the use of prokaryotes, fungi, or plants to remove pollutants from the environment. This process has been used to remove harmful toxins in groundwater as a byproduct of agricultural run-off and also to clean up oil spills.