Stepwise degradation of bisphenol A into various monocyclic aromatic hydrocarbons by a P450 enzyme BisdB in Sphingobium yanoikuyae GDP.

Bisphenol A (BPA) is a frequently used endocrine-disrupting chemical widely distributed in the environment, necessitating effective removal strategies. This study aimed to isolate and characterize a highly efficient BPA-degrading bacterial strain, Sphingobium yanoikuyae GDP, and to elucidate the enzymatic degradation pathways of BPA mediated by the P450 enzyme BisdB, including the identification of novel metabolites using C stable isotope-assisted untargeted liquid chromatography-tandem mass spectrometry. In this study, a BPA-degrading microbial community, D45, was isolated from contaminated soil and degraded 400 mg L of BPA within 24 h. Ten metabolites were identified during BPA degradation by D45, including 4,4'-dihydroxybenzophenone (4-DHBP), a novel metabolite. Sphingobium yanoikuyae strain GDP was subsequently obtained, which degraded BPA via the same routes as D45 but exhibited enhanced BPA-degrading efficiency. Genomic and gene expression analyses revealed that a P450 enzyme BisdB was essential for BPA degradation. BisdB produced at least eight metabolites, including 4-DHBP, through stepwise BPA catalysis, two of which were challenging to transform further. This study revealed the precise role of bacterial P450 in BPA degradation and illustrated the complete BPA degradation pathways. These findings provide potential opportunities for synthetic biology-based applications of the GDP strain and BisdB to degrade BPA.