Effect of copper ion and soil humic acid on biodegradation of decabromodiphenyl ether (BDE‐209) by Pseudomonas aeruginosa

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+).