The 4-tert-Butylphenol-Utilizing Bacterium Sphingobium fuliginis OMI Can Degrade Bisphenols via Phenolic Ring Hydroxylation and Meta-Cleavage Pathway

Recently, we showed that Sphingobium fuliginis OMI utilizes 4-tert-butylphenol as a sole carbon and energy source via phenolic ring hydroxylation followed by a meta-cleavage pathway, and that this strain can degrade various alkylphenols. Here, we showed that strain OMI effectively degrades bisphenol A (BPA) via the pathway in which one or two of the phenolic rings of BPA is initially hydroxylated without any modification of the alkyl group that binds the two phenolic rings, and then the aromatic ring is cleaved via a meta-cleavage pathway. Strain OMI also degraded other bisphenols, including bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)sulfone (BPS), 2,2-bis(4-hydroxyphenyl)butane, bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 4,4'-thiodiphenol (TDP), and 4,4'-dihydroxybenzophenone via phenolic ring hydroxylation and meta-cleavage pathway. To our knowledge, this is the first report to describe the aerobic biodegradation of BPS and TDP. The bisphenols degradation pathway of strain OMI is completely different from the known degradation pathways of BPA or bisphenols, and unique in that it does not appear to be influenced by the chemical structure that binds the two phenolic rings. This newly found pathway may play a certain part in the environmental fate of bisphenols and biotreatment/bioremediation of various bisphenols.