Removal of BPA by Pseudomonas asiatica P1: Synergistic response mechanism of toxicity resistance and biodegradation

Bisphenol A (BPA) is a globally concerning toxic pollutant, and microbial degradation is considered an effective method to treat BPA contamination. However, the inherent microbial toxicity of BPA is often overlooked, particularly the microbial mechanisms of resistance and detoxification against BPA. This study found that under the toxic stress of BPA, cbb3-type cytochrome c oxidase (cbb3-Cox) in the cells of Pseudomonas asiatica P1 (P. asiatica P1) was the first to resist the toxicity. Genes such as ccoNOQPG showed significant upregulation with an average log₂^FC value of 3.56. Subsequently, genes that are related to metal ion binding, transport, and DNA repair were upregulated in the middle to later phase, which enhanced the metabolic functions of the strains and induced strain mutations to assist P. asiatica P1 in resisting the BPA toxicity. Meanwhile, three potential BPA degradation genes were identified, among which sdr_P1 was crucial to the BPA degradation and detoxification. After genetic recombination, sdr_P1 achieved a degradation rate of 92.52 % for BPA. Furthermore, through various methods such as alkyl interactions, sdr_P1 exhibited oxidation and demethylation to form lower toxic intermediate products and complete the biological detoxification of BPA. This study provides a systematic analysis of the toxicity resistance, biodegradation, and detoxification processes in bacterial BPA removal, refines the mechanism of BPA biodegradation and contributes to a more comprehensive and systematic understanding of the overall process of microbial removal of toxic pollutants.