Abstract
Pseudomonas aeruginosa is a good environmental microorganism capable of degrading decabromodiphenyl ether (BDE-209). This paper studied the effect of Cu(2+) and humic acid (HA) extracted from e-waste contaminated soils on biodegradation of BDE-209 by P. aeruginosa. The adsorption isotherms of Cu(2+) on HA, the crude enzyme activity, cell surface morphology, and biodegradation pathway were also investigated. The results showed that BDE-209 biodegradation by P. aeruginosa was inhibited at Cu(2+) concentrations above 5 mg L(-1) , but exhibited the best effect at the condition of 40 mg L(-1) Cu(2+) + 3 g L(-1) HA. At the condition of 40 mg L(-1) Cu(2+) + 3 g L(-1) HA, 97.35 ± 2.33% of the initial BDE-209 was degraded after 5 days, debromination efficiency was 72.14 ± 1.89%, crude enzyme activity reached the maximum of 0.519 ± 0.022U g(-1) protein, cell surface of P. aeruginosa was smooth with normal short-rod shapes, and biodegradation pathway mainly include debromination, hydroxylation, and cleavage of the diphenyl ether bond. It was suggested that soil HA could eliminate the toxic effect of high Cu(2+) concentrations and biodegradation of BDE-209 was improved by synergistic effect of HA and Cu(2+) .