Biodegradation and Bioaccumulation of Decachlorobiphenyl (DCB) by Native Strain Pseudomonas extremaustralis ADA-5

Abstract

Decachlorobiphenyl (DCB) is one of the 209 polychlorinated biphenyls congeners characterized by its high toxicity and chemical stability. It is produced by industrial activities. A possible strategy to eliminate DCB is by bacterial degradation. The main objective of this study was to define the optimal conditions for biodegradation and bioaccumulation of DCB by Pseudomonas extremaustralis ADA-5 isolated from a worm intestine. Bacterial growth kinetics were determined in minimal medium with added biphenyl and DCB. By GC coupled to mass spectrometry, we found that the strain had the ability to degrade 9.75% of available DCB, using it as a carbon source and was able to accumulate 19.98% of this pollutant in biomass. Membrane lipids may be altered by DCB. Phosphatidylethanolamine (PE), phosphatidylglycerol (PG), and cardiolipin (CL) were identified by thin-layer chromatography as the membrane lipids of the cell. At 250 mg L⁻¹ of DCB in the culture medium, membranes showed a 30% decrease in the PE concentration, an 18% increase in the PG, and a 12% increase in CL. ADA-5 was able to catabolize DCB and may be used for bioremediation of highly chlorinated toxic compounds in soil.