Effect of cadmium ion on biodegradation of decabromodiphenyl ether (BDE-209) by Pseudomonas aeruginosa

The influence of Cd(II) ions on the degradation of decabromodiphenyl ether (BDE-209) by an aerobic degrading strain, Pseudomonas aeruginosa, was investigated. The results demonstrated that the strain P. aeruginosa exhibited a high level of resistance against cadmium toxicity, and Cd(II) ions of different concentrations possessed mixed reactions on BDE-209 bioremoval. The degradation efficiency was stimulated at low concentrations of Cd(II) ions (≤ 1 mg L(-1)) but inhibited at higher levels (≥ 5 mg L(-1)). Subsequent analyses revealed that the increase of cell hydrophobicity and membrane permeability were two main factors for Cd(II) ions of low concentrations to accelerate BDE-209 degradation. However, inhibition effect by high concentrations of Cd(II) ions was mainly attributed to the negative impact of metals on growth and metabolism of the strain. It was also showed through cellular distribution of BDE-209 that different concentration of Cd(II) ions affected the amount of BDE-209 inside or outside the cell at different incubation time.