ABSTRACT
Bioremediation of sediment organic pollution has been intensely investigated, but the degradation of complex organic compounds, pesticide residues, and polychlorinated biphenyls (PCBs) remains poorly studied. In this study, sediments were collected from Zhanjiang Mangrove Reserve and inoculated in an inorganic salt medium using only biphenyl (BP) and PCBs as the carbon sources to obtain a PCB-degrading strain. A gram-negative bacterium that metabolized PCBs was isolated and identified as Klebsiella Lw3 by 16S rDNA phylogenetic analysis. Genomic sequencing showed that this bacterium possessed genes related to BP/PCB degradation, and its GC content was 58.2%; we identified 3326 cellular pathways. Gas chromatography–mass spectrometry was employed to test the PCB degrading ability; the results showed that the strain had a good degradation effect on PCB3 at concentrations of 5, 10, 20, 40, and 60 mg/L and that the final degradation rate was higher than 97% after 96 h. Interestingly, this strain showed good biodegradability of PCBs despite having no classical PCB degradation pathway, providing a new direction for Klebsiella research with practical significance for in situ bioremediation of PCB contamination. Overall, this study provides valuable insights into the genetic structure of PCB-degrading strains as well as eco-friendly and low-cost PCB degradation and lays a foundation for the discovery of new degradation pathways.
GRAPHICAL ABSTRACT
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Acknowledgments
The authors are grateful to the staff of the College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, China, for providing technical assistance and support during the course of the study. This research was supported by the Marine Economic Development Project of Guangdong Province Special Fund for Promoting High-quality Economic Development (Contract grant number: GDOE2019A52), Guangdong Postgraduate Education Innovation Project (2020SFJD001), and International Science and Technology Cooperation Project of Guangdong Province (Contract grant number: 2016A050502062).
Geolocation information
China
Declaration of interest statement
The authors report there are no competing interests to declare.
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Data availability statement
The data that support the findings of this study are available on request from the corresponding author [Chen. J.-J].
Disclosure statement
No potential conflict of interest was reported by the authors .