Transcriptome analysis and cytochrome P450 monooxygenase reveal the molecular mechanism of Bisphenol A degradation by Pseudomonas putida strain YC-AE1

Background Bisphenol A (BPA) is a rapid spreading organic pollutant that widely used in many industries especially as a plasticizer in polycarbonate plastic and epoxy resins.

BPA reported as a prominent endocrine disruptor compound that possesses estrogenic activity and fulminant toxicity.

Pseudomonas putida  YC-AE1 was isolated in our previous study and exerted a strong degradation capacity toward BPA at high concentrations; however, the molecular degradation mechanism is still enigmatic.

Results We employed RNA sequencing to analyze the differentially expressed genes (DEGs) in the YC-AE1 strain upon BPA induction.

Out of 1229 differentially expressed genes, 725 genes were positively regulated, and 504 genes were down-regulated.

The pathways of microbial metabolism in diverse environments were significantly enriched among DEGs based on KEGG enrichment analysis.

qRT-PCR confirm the involvement of BPA degradation relevant genes in accordance with RNA Seq data.

The degradation pathway of BPA in YC-AE1 was proposed with specific enzymes and encoded genes.

The role of cytochrome P450 (CYP450) in BPA degradation was further verified.

Sever decrease in BPA degradation was recorded by YC-AE1 in the presence of CYP450 inhibitor.

Subsequently, CYP450 bisdB  deficient YC-AE1 strain △  bisdB lost its ability toward BPA transformation comparing with the wild type.

Furthermore, Transformation of  E. coli  with pET-32a- bisdAB  empowers it to degrade 66 mg l^−1 of BPA after 24 h. Altogether, the results showed the role of CYP450 in biodegradation of BPA by YC-AE1.

Conclusion In this study we propose the molecular basis and the potential role of YC-AE1cytochrome P450 monooxygenase in BPA catabolism.