Isolation of microalgae tolerant to polybrominated diphenyl ethers (PBDEs) from wastewater treatment plants and their removal ability

• Nine microalgal strains were isolated from influents of WWTPs spiked with PBDEs.
• The isolates were identified based on the morphological and 18S rDNA analysis.
• The tolerance and removal ability of different isolates to PBDEs were compared.
• A Chlorella isolate with high tolerance to PBDEs and removal ability was obtained.
• Bioaccumulation and biotransformation were important for PBDE removal.

The present study isolated microalgae with tolerance to polybrominated diphenyl ethers (PBDEs) from wastewater aiming to discover isolates with high removal abilities. Nine isolates, Chlorella (STCh and SICh), Parachlorella (STPa1 and STPa2), Scenedesmus (STSc, TPSc1 and TPSc2), Nitzschia palea (YLBa) and Mychonastes (TPMy), were obtained. Four isolates, SICh, STCh, STPa1 and TPSc1, were very tolerant, and their growth was not affected by DE-71 and BDE-209 mixtures (5:1) at low (6 μg L−1), medium (60 μg L−1) or even high (600 μg L−1) levels for 7 days. The removal of PBDEs by one of the tolerant isolates, SICh, was the highest, with 82–90% removal at the end of 7-days exposure. SICh also accumulated more PBDEs than the other isolates. Bioaccumulation and biotransformation were important for PBDE removal. This is the first study isolated PBDE-tolerant microalgae from wastewater and obtained a Chlorella isolate, SICh, with high tolerance and removal ability.