Biotransformation of the flame retardant tetrabromobisphenol-A (TBBPA) by freshwater microalgae

Tetrabromobisphenol-A (TBBPA) is the most widely used brominated flame retardant. However, little is known about its biotransformation by algae in aquatic environments. The authors investigated transformations of TBBPA by 6 freshwater green microalgae and identified its transformation products. Transformation experiments were conducted under axenic conditions in a laboratory for 10 d. The results showed that TBBPA could be transformed by the selected microalgae, with nearly complete removal by Scenedesmus quadricauda and Coelastrum sphaericum following 10-d incubation. Five transformation products were positively identified by mass spectrometry: TBBPA sulfate, TBBPA glucoside, sulfated TBBPA glucoside, TBBPA monomethyl ether, and tribromobisphenol-A. The mechanisms involved in the biotransformation of TBBPA include sulfation, glucosylation, O-methylation, and debromination, which could be an important step for its further degradation. This suggests that microalgae can play an important role in the fate of TBBPA in aquatic environments. The present study is the first report on algal transformation of TBBPA, and the proposed transformation products could have significant environmental implications.