Deciphering the triclosan degradation mechanism in Sphingomonas sp. strain YL-JM2C: Implications for wastewater treatment and marine resources.

Triclosan (TCS), an antimicrobial agent extensively incorporated into pharmaceuticals and personal care products, poses significant environmental risks because of its persistence and ecotoxicity. So far, a few microorganisms were suggested to degrade TCS, but the microbial degradation mechanism remains elusive. Here, a two-component angular dioxygenase (TcsAaAb) responsible for the initial TCS degradation was characterized in Sphingomonas sp. strain YL-JM2C. Whole-cell biotransformation and crude enzyme assays demonstrated that TcsAaAb catalyzed the conversion of TCS to 4-chlorocatechol and 3,5-dichlorocatechol rather than the commonly suggested product 2,4-dichlorophenol. Then two intermediates were catabolized by tcsCDEF cluster via an ortho-cleavage pathway. Critical residues (N262, F279, and F391) for substrate binding were identified via molecular docking and mutagenesis. Further, TcsAaAb showed activity toward methyl triclosan and nitrofen, suggesting its versatile potential for bioremediation. In addition, TCS-degrading genes were also present in diverse bacterial genomes in wastewater, ocean and soil, and a relatively high gene abundance was observed in marine metagenomes, revealing the transformation fate of TCS in environments and the microbial potential in pollutant removal. These findings extend the understanding of the microbe-mediated TCS degradation and contribute to the mining of TCS-degrading strains and enzymes, as well as their application in the bioremediation of contaminated environments.

Pan P ，Gu Y ，Li T ，Zhou NY ，Xu Y ... -  《-》

Triclosan Dioxygenase: A Novel Two-component Rieske Nonheme Iron Ring-hydroxylating Dioxygenase Initiates Triclosan Degradation.

Yin Y ，Ren H ，Wu H ，Lu Z ... -  《-》

Characterization of triclosan metabolism in Sphingomonas sp. strain YL-JM2C.

Mulla SI ，Wang H ，Sun Q ，Hu A ，Yu CP ... -  《Scientific Reports》

Degradation of triclocarban by a triclosan-degrading Sphingomonas sp. strain YL-JM2C.

Bacterial degradation plays a vital role in determining the environmental fate of micropollutants like triclocarban. The mechanism of triclocarban degradation by pure bacterium is not yet explored. The purpose of this study was to identify metabolic pathway that might be involved in bacterial degradation of triclocarban. Triclosan-degrading Sphingomonas sp. strain YL-JM2C was first found to degrade up to 35% of triclocarban (4 mg L(-1)) within 5 d. Gas chromatography-mass spectrometry detected 3,4-dichloroaniline, 4-chloroaniline and 4-chlorocatechol as the major metabolites of the triclocarban degradation. Furthermore, total organic carbon results confirmed that the intermediates, 3,4-dichloroaniline (4 mg L(-1)) and 4-chloroaniline (4 mg L(-1)) could be degraded up to 77% and 80% by strain YL-JM2C within 5 d.

Mulla SI ，Hu A ，Wang Y ，Sun Q ，Huang SL ，Wang H ，Yu CP ... -  《-》

Identification of a gene cluster associated with triclosan catabolism.

Kagle JM ，Paxson C ，Johnstone P ，Hay AG ... -  《-》