title: Identification of triclosan-degrading bacteria in a triclosan enrichment culture using stable isotope probing.
abstract: Triclosan, a widely used antimicrobial agent, is an emerging contaminant in the environment. Despite its antimicrobial character, biodegradation of triclosan has been observed in pure cultures, soils and activated sludge. However, little is known about the microorganisms responsible for the degradation in mixed cultures. In this study, active triclosan degraders in a triclosan-degrading enrichment culture were identified using stable isotope probing (SIP) with universally (13)C-labeled triclosan. Eleven clones contributed from active microorganisms capable of uptake the (13)C in triclosan were identified. None of these clones were similar to known triclosan-degraders/utilizers. These clones distributed among α-, β-, or γ-Proteobacteria: one belonging to Defluvibacter (α-Proteobacteria), seven belonging to Alicycliphilus (β-Proteobacteria), and three belonging to Stenotrophomonas (γ-Proteobacteria). Successive additions of triclosan caused a significant shift in the microbial community structure of the enrichment culture, with dominant ribotypes belonging to the genera Alicycliphilus and Defluvibacter. Application of SIP has successfully identified diverse uncultivable triclosan-degrading microorganisms in an activated sludge enrichment culture. The results of this study not only contributed to our understanding of the microbial ecology of triclosan biodegradation in wastewater, but also suggested that triclosan degraders are more phylogenetically diverse than previously reported.
authors.affiliation: Zachry Department of Civil Engineering, Texas A&M University, 205G WERC, 3136 TAMU, College Station, TX, 77843-3136, USA.
authors.forename: Do Gyun
authors.initials: DG
authors.lastname: Lee
authors.forename: Kun-Ching
authors.initials: KC
authors.lastname: Cho
authors.forename: Kung-Hui
authors.initials: KH
authors.lastname: Chu
mesh_terms: D020561:Alphaproteobacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D000891:Anti-Infective Agents, Local / Q000378:metabolism*; D020562:Betaproteobacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D001673:Biodegradation, Environmental; D002247:Carbon Isotopes; D004785:Environmental Pollutants / Q000378:metabolism*; D020563:Gammaproteobacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000145:classification / Q000235:genetics; D012722:Sewage / Q000737:chemistry; D014260:Triclosan / Q000378:metabolism*
chemical_list: D000891:Anti-Infective Agents, Local; D002247:Carbon Isotopes; D004785:Environmental Pollutants; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D014260:Triclosan