Aerobic biodegradation of 2,2',4,4'-tetrabrominated diphenyl ether (BDE-47) by Phanerochaete chrysosporium in the presence of Cd2+ was investigated in this study. The results showed that P. chrysosporium could effectively degrade BDE-47, and its extracellular enzyme played an important role in the process of decomposition. BDE-47 biodegradation by fungi was more tolerant than extracellular enzyme in the presence of Cd2+. Also, both of the activity of two typical enzymes, MnP and LiP, descended with ascended Cd2+ concentration. Based on the four mono-hydroxylated PBDEs (5-OH-BDE-47, 4'-OH-BDE-17, 6-OH-BDE-47, and 2'-OH-BDE-28) and two bromophenols (2,4-DBP, 4-BP) detected, three possible degradation pathways were proposed, inferring that BDE-47 was more easily to transform via hydroxylation. With addition of Cd2+, the types of degradation products did not change, merely a variation of the content of these products observed. Meanwhile, the major metabolites of BDE-47, bromophenol compounds, have been found to be transformed or even mineralized by P. chrysosporium quickly, which also helped better explain why the amounts of BDE-47 decomposed did not match with that of the metabolites detected.
Keywords: BDE-47 biodegradation; Bromophenols; Cadmium ions; OH-PBDEs; Phanerochaete chrysosporium.