A Pseudomonas putida Strain Genetically Engineered for 1,2,3-Trichloropropane Bioremediation.
| Authors | |
|---|---|
| Year of publication | 2014 |
| Type | Article in Periodical |
| Magazine / Source | Applied and Environmental Microbiology |
| MU Faculty or unit | |
| Citation | |
| Doi | http://dx.doi.org/10.1128/AEM.01620-14 |
| Field | Biochemistry |
| Keywords | 1; 2;3-Trichloropropane; biodegradation; Pseudomonas putida MC4 |
| Description | 1,2,3-Trichloropropane (TCP) is a toxic compound that is recalcitrant to biodegradation in the environment and attempts to isolate TCP-degrading organisms using enrichment cultivation have failed. A potential biodegradation pathway starts with hydrolytic dehalogenation to 2,3 dichloro-1-propanol (DCP), followed by oxidative metabolism. To obtain a practically applicable TCP-degrading organism, we introduced an engineered haloalkane dehalogenase with improved TCP degradation activity into the DCP-degrading bacterium Pseudomonas putida MC4. For this, the dehalogenase gene (dhaA31) was cloned behind the constitutive dhlA promoter and introduced into the genome of strain MC4 using a transposon delivery system. The transposon-located antibiotic resistance marker was subsequently removed using a resolvase step. Growth of the resulting engineered bacterium P. putida MC4-5222 on TCP was indeed observed, and all organic chlorine was released as chloride. A packed-bed reactor with immobilized cells of strain MC4 5222 degraded >95% of influent TCP (0.33 mM) under continuous flow conditions, with stoichiometric release of inorganic chloride. The results show the use of a laboratory-evolved dehalogenase and genetic engineering for obtaining an effective plasmid-free and stable whole-cell biocatalyst for the aerobic bioremediation of a recalcitrant chlorinated hydrocarbon. |
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