Identification of triclosan-degrading bacteria using stable isotope probing, fluorescence in situ hybridization and microautoradiography

Lolas, Ihab Bishara Yousef; Chen, Xijuan; Bester, Kai; Nielsen, Jeppe Lund

doi:10.1099/mic.0.061077-0

Cited by 36 publications

(12 citation statements)

References 52 publications

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“…However, guided by the artificial stream results, we did detect a strong correlation between triclosan concentration and relative abundance of Methylococcales. A recent study demonstrated that Methylobacillus was the predominant organism utilizing triclosan as a carbon source in an enrichment culture from activated sludge (Lolas, et al, 2012). While Methylococcales (Gammaproteobacteria) and Methylobacillus (Betaproteobacteria) are not closely related phylogenetically, they are both methylotrophs.…”

Section: Field Studymentioning

confidence: 99%

Triclosan Exposure Increases Triclosan Resistance and Influences Taxonomic Composition of Benthic Bacterial Communities

Drury

Scott²,

Rosi‐Marshall

et al. 2013

Environ. Sci. Technol.

175

114

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Triclosan (TCS) is a broad-spectrum antimicrobial compound that is incorporated into numerous consumer products. TCS has been detected in aquatic ecosystems across the U.S., raising concern about its potential ecological effects. We conducted a field survey and an artificial stream experiment to assess effects of TCS on benthic bacterial communities. Field sampling indicated that TCS concentrations in stream sediments increased with degree of urbanization. There was significant correlation between sediment TCS concentration and the proportion of cultivable benthic bacteria that were resistant to TCS, demonstrating that the levels of TCS present in these streams was affecting the native communities. An artificial stream experiment confirmed that TCS exposure could trigger increases in TCS resistance within cultivable benthic bacteria, and pyrosequencing analysis indicated that TCS resulted in decreased benthic bacterial diversity and shifts in bacterial community composition. One notable change was a 6-fold increase in the relative abundance of cyanobacterial sequences and a dramatic die-off of algae within the artificial streams. Selection of cyanobacteria over algae could have significant implications for higher trophic levels within streams. Finally, there were no observed effects of TCS on bacterial abundance or respiration rates, suggesting that bacterial density and function were highly resilient to TCS exposure.

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Section: Field Studymentioning

confidence: 99%

Triclosan Exposure Increases Triclosan Resistance and Influences Taxonomic Composition of Benthic Bacterial Communities

Drury

Scott²,

Rosi‐Marshall

et al. 2013

Environ. Sci. Technol.

175

114

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“…As in many other research areas, the rapid increase in sequence information pushed forward techniques which facilitated the elucidation and systemic understanding of biodegradation pathways. These techniques were also applied to wastewater treatment to varying extents, ranging from qPCR (Helbling et al., 2012b) to FISH (Ettwig et al., 2009, Lolas et al., 2012), metagenomics (Martin et al., 2006) or metatranscriptomics (Helbling et al., 2012a), 16S-amplicon based taxonomic community profiling (Vanwonterghem et al., 2014) and metaproteomics (Collado et al., 2013, Hansen et al., 2014, Wilmes et al., 2008). …”

Section: Introductionmentioning

confidence: 99%

Micropollutant degradation via extracted native enzymes from activated sludge

et al. 2016

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A procedure was developed to assess the biodegradation of micropollutants in cell-free lysates produced from activated sludge of a municipal wastewater treatment plant (WWTP). This proof-of-principle provides the basis for further investigations of micropollutant biodegradation via native enzymes in a solution of reduced complexity, facilitating downstream protein analysis. Differently produced lysates, containing a variety of native enzymes, showed significant enzymatic activities of acid phosphatase, β-galactosidase and β-glucuronidase in conventional colorimetric enzyme assays, whereas heat-deactivated controls did not. To determine the enzymatic activity towards micropollutants, 20 compounds were spiked to the cell-free lysates under aerobic conditions and were monitored via LC-ESI-MS/MS. The micropollutants were selected to span a wide range of different biodegradabilities in conventional activated sludge treatment via distinct primary degradation reactions. Of the 20 spiked micropollutants, 18 could be degraded by intact sludge under assay conditions, while six showed reproducible degradation in the lysates compared to the heat-deactivated negative controls: acetaminophen, N-acetyl-sulfamethoxazole (acetyl-SMX), atenolol, bezafibrate, erythromycin and 10,11-dihydro-10-hydroxycarbamazepine (10-OH-CBZ). The primary biotransformation of the first four compounds can be attributed to amide hydrolysis. However, the observed biotransformations in the lysates were differently influenced by experimental parameters such as sludge pre-treatment and the addition of ammonium sulfate or peptidase inhibitors, suggesting that different hydrolase enzymes were involved in the primary degradation, among them possibly peptidases. Furthermore, the transformation of 10-OH-CBZ to 9-CA-ADIN was caused by a biologically-mediated oxidation, which indicates that in addition to hydrolases further enzyme classes (probably oxidoreductases) are present in the native lysates. Although the full variety of indigenous enzymatic activity of the activated sludge source material could not be restored, experimental modifications, e.g. different lysate filtration, significantly enhanced specific enzyme activities (e.g. >96% removal of the antibiotic erythromycin). Therefore, the approach presented in this study provides the experimental basis for a further elucidation of the enzymatic processes underlying wastewater treatment on the level of native proteins.

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“…KCY (Lee et al 2012), Mycobacterium vaccae JOB5 and Rhodococcus jostii RHA1 , have also been reported to catabolize triclosan. Methylobacillus was implicated as a triclosan assimilating organism in one stable isotope study of a sewage sludge-derived enrichment culture (Lolas et al 2012) while uncultured AlicycliphilusḐ efluvibacter and Stenotrophomonas were implicated in another .…”

Section: Introductionmentioning

confidence: 99%

Identification of a gene cluster associated with triclosan catabolism

2015

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Aerobic degradation of bis-aryl ethers like the antimicrobial triclosan typically proceeds through oxygenase-dependent catabolic pathways. Although several studies have reported on bacteria capable of degrading triclosan aerobically, there are no reports describing the genes responsible for this process. In this study, a gene encoding the large subunit of a putative triclosan oxygenase, designated tcsA was identified in a triclosan-degrading fosmid clone from a DNA library of Sphingomonas sp. RD1. Consistent with tcsA's similarity to two-part dioxygenases, a putative FMN-dependent ferredoxin reductase, designated tcsB was found immediately downstream of tcsA. Both tcsAB were found in the midst of a putative chlorocatechol degradation operon. We show that RD1 produces hydroxytriclosan and chlorocatechols during triclosan degradation and that tcsA is induced by triclosan. This is the first study to report on the genetics of triclosan degradation.

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Identification of triclosan-degrading bacteria using stable isotope probing, fluorescence in situ hybridization and microautoradiography

Cited by 36 publications

References 52 publications

Triclosan Exposure Increases Triclosan Resistance and Influences Taxonomic Composition of Benthic Bacterial Communities

Triclosan Exposure Increases Triclosan Resistance and Influences Taxonomic Composition of Benthic Bacterial Communities

Micropollutant degradation via extracted native enzymes from activated sludge

Identification of a gene cluster associated with triclosan catabolism

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