Profiling 5-tolyltriazole biodegrading sludge communities using next-generation sequencing and denaturing gradient gel electrophoresis

Syst Appl Microbiol. 2017 Dec;40(8):508-515. doi: 10.1016/j.syapm.2017.09.007. Epub 2017 Nov 3.

Abstract

Efficient biodegradation of 5-tolyltriazole (5-TTri) in wastewater treatment would minimize its potential detrimental effects on aquatic systems. Therefore, in order to profile 5-TTri biodegrading activated sludge communities (ASC) by DGGE and NGS, acclimation experiments with (i) easily degradable substrates, and (ii) various complex substrates mimicking wastewater conditions were performed. DGGE revealed four genera: Aminobacter (family Phyllobacteriaceae), Flavobacterium (family Flavobacteriaceae), Pseudomonas (family Pseudomonaceae), and Hydrogenophaga (family Comamonadaceae). Metagenomics (DNA) revealed the dominant families Alcaligenaceae, Pseudomonadaceae and Comamonadaceae that also represented the most active families at the RNA level (metatranscriptomics), which might indicate their importance for 5-TTri biodegradation. ASC acclimation and the composition of the substrate significantly affected 5-TTri biodegradation and the development of biodegrading communities. Using acetate only, a moderate 5-TTri degrading community was detected with a very low biodiversity and Pseudomonas spp. as dominant organisms. In contrast, setups fed 'sludge supernatant' (a complex substrate) efficiently biodegraded 5-TTri and formed a more diverse microbial community but with Hydrogenophaga spp. as the dominant group. Finally, a hypothetical 5-TTri biodegradation pathway was constructed based exclusively on the detected, biodegradation-related, Hydrogenophaga spp. genes.

Keywords: 5-Methyl-benzotriazole; Activated sludge; Metagenome; Metatranscriptome; Micropollutants; Xenobiotic.

MeSH terms

  • Betaproteobacteria / classification
  • Betaproteobacteria / isolation & purification
  • Betaproteobacteria / metabolism
  • Biodegradation, Environmental
  • Bioreactors / microbiology*
  • Comamonadaceae / isolation & purification
  • Comamonadaceae / metabolism
  • Denaturing Gradient Gel Electrophoresis / methods
  • Flavobacterium / isolation & purification
  • Flavobacterium / metabolism
  • High-Throughput Nucleotide Sequencing
  • Phyllobacteriaceae / classification
  • Phyllobacteriaceae / isolation & purification
  • Phyllobacteriaceae / metabolism
  • Pseudomonas / isolation & purification
  • Pseudomonas / metabolism
  • Sewage / microbiology*
  • Triazoles / analysis
  • Triazoles / metabolism*
  • Water Pollutants, Chemical / analysis
  • Water Pollutants, Chemical / metabolism*

Substances

  • Sewage
  • Triazoles
  • Water Pollutants, Chemical
  • 5-tolyltriazole