Co-metabolic Biotransformation of Bisphenol AF by a Bisphenol A-Growing Bacterial Enrichment Culture

The fluorinated bisphenol A (2,2-bis[4-hydroxyphenyl]propane, BPA) substitute bisphenol AF (BPAF) could be more persistent and toxic than BPA, but little is known about its environmental fate. In this study, we established a co-metabolic BPAF-degrading bacterial enrichment culture with BPA as the growth substrate. BPAF degradation by the enrichment culture was dependent on BPA, and BPAF could be eliminated to below the detection limit with successive additions of BPA. BPAF was mainly degraded via phenolic ring hydroxylation and sequential ring cleavage, which are minor BPA transformation pathway. Conjugated BPAF products were also identified based on the characteristic CF₃^- fragment and were found to accumulate during BPAF degradation. Sphingopyxis was the key BPA and BPAF degrader in the aerobic enrichment cultures, which was the most abundant genera in only BPA-added and BPA and BPAF-added cultures and was proven to be able to degrade BPA and BPAF by isolation. The aerobic co-metabolic BPAF degrading community also contain non-BPA and BPAF degraders, such as Pandoraea, which may play a supporting role in the community.