A Pseudomonas putida strain genetically engineered for 1,2,3-trichloropropane bioremediation
Ghufrana Samin1, Martina Pavlova2, M Irfan Arif3
1Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands Department of Chemistry, University of Engineering and Technology Lahore, Faisalabad Campus, Faisalabad, Pakistan.
Applied and Environmental Microbiology
|June 29, 2014
Summary
Engineered bacteria can now degrade toxic 1,2,3-Trichloropropane (TCP). This breakthrough offers a stable, whole-cell biocatalyst for bioremediation of recalcitrant chlorinated hydrocarbons.
Area of Science:
- Environmental microbiology
- Biotechnology
- Bioremediation
Background:
- 1,2,3-Trichloropropane (TCP) is a persistent environmental pollutant resistant to biodegradation.
- Previous attempts to isolate TCP-degrading microorganisms have been unsuccessful.
- A proposed pathway involves dehalogenation to 2,3-dichloro-1-propanol (DCP) followed by oxidation.
Purpose of the Study:
- To develop an effective whole-cell biocatalyst for 1,2,3-Trichloropropane (TCP) bioremediation.
- To engineer a bacterium capable of degrading TCP using a laboratory-evolved dehalogenase.
- To create a stable, plasmid-free microbial strain for environmental applications.
Main Methods:
- Genetic engineering of Pseudomonas putida MC4 by introducing an enhanced haloalkane dehalogenase gene (dhaA31).
- Utilized a transposon delivery system for stable genomic integration of the dehalogenase gene.
- Removed antibiotic resistance marker via a resolvase system, creating a plasmid-free strain (P. putida MC4-5222).
- Tested the engineered strain in a packed-bed reactor with immobilized cells for continuous TCP degradation.
Main Results:
- Engineered P. putida MC4-5222 demonstrated growth on TCP, releasing all organic chlorine as chloride.
- A packed-bed bioreactor achieved >95% degradation of influent TCP (0.33 mM) under continuous flow.
- Stoichiometric release of inorganic chloride confirmed complete dechlorination.
Conclusions:
- Successfully engineered a stable, plasmid-free biocatalyst for aerobic bioremediation of recalcitrant chlorinated hydrocarbons.
- Demonstrated the efficacy of a laboratory-evolved dehalogenase in a whole-cell system.
- Validated the use of genetic engineering for developing practical microbial solutions for environmental pollutants.
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