Effects of glucose and biphenyl on aerobic cometabolism of polybrominated diphenyl ethers by Pseudomonas putida: Kinetics and degradation mechanism

Polybrominated diphenyl ethers (PBDEs) are emerging persistent organic pollutants and the degradation of PBDEs is still a tremendous challenge owing to their extreme persistence and recalcitrance. In this study, Pseudomonas putida was employed for bioremediation of four PBDE congeners (BDE47, 15, 3 and diphenyl ether (DE)) with an initial concentration of 2 mg/L and the cometabolism of PBDEs was illustrated via kinetics analysis and metabolic mechanism. The biodegradation kinetics analysis suggested that PBDEs was inversely proportional to the number of bromine substituted on diphenyl ether. Both glucose (24 mg/L) and biphenyl (10 mg/L) played a positive role in promoting the biodegradation of PBDEs. The growth kinetics analysis indicated that glucose had uncompetitive inhibition on PBDEs consumption while both competitive and uncompetitive inhibition existed in biphenyl-PBDEs binary substrate system. Furthermore, the intermediates were identified by GC–MS and the main tentative degradation pathways were proposed. The angular dioxygenation was the main pathway for PBDEs degradation, while lateral dioxygenation could be induced when biphenyl was added.