Integrated multi-omics investigations reveal the key role of synergistic microbial networks in removing plasticizer di-(2-ethylhexyl) phthalate from estuarine sediments

Sean Ting-Shyang Wei, Yi Lung Chen, Yu Wei Wu, Tien Yu Wu, Yi Li Lai, Po Hsiang Wang, Wael Ismail, Tzong Huei Lee, Yin Ru Chiang

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Di-(2-ethylhexyl) phthalate (DEHP) is the most widely used plasticizer worldwide, with an annual global production of more than 8 million tons. Because of its improper disposal, endocrine-disrupting DEHP often accumulates in estuarine sediments in industrialized countries at submillimolar levels, resulting in adverse effects on both ecosystems and human beings. The microbial degraders and biodegradation pathways of DEHP in O2-limited estuarine sediments remain elusive. Here, we employed an integrated meta-omics approach to identify the DEHP degradation pathway and major degraders in this ecosystem. Estuarine sediments were treated with DEHP or its derived metabolites, o-phthalic acid and benzoic acid. The rate of DEHP degradation in denitrifying mesocosms was two times slower than that of o-phthalic acid, suggesting that side chain hydrolysis of DEHP is the rate-limiting step of anaerobic DEHP degradation. On the basis of microbial community structures, functional gene expression, and metabolite profile analysis, we proposed that DEHP biodegradation in estuarine sediments is mainly achieved through synergistic networks between denitrifying proteobacteria. Acidovorax and Sedimenticola are the major degraders of DEHP side chains; the resulting o-phthalic acid is mainly degraded by Aestuariibacter through the UbiD-dependent benzoyl coenzyme A (benzoyl-CoA) pathway. We isolated and characterized Acidovorax sp. strain 210- 6 and its extracellular hydrolase, which hydrolyzes both alkyl side chains of DEHP. Interestingly, genes encoding DEHP/mono-(2-ethylhexyl) phthalate (MEHP) hydrolase and phthaloyl-CoA decarboxylase-key enzymes for side chain hydrolysis and o-phthalic acid degradation, respectively-are flanked by transposases in these proteobacterial genomes, indicating that DEHP degradation capacity is likely transferred horizontally in microbial communities.

Original languageEnglish
Article numbere00358-21
JournalmSystems
Volume6
Issue number3
DOIs
Publication statusPublished - Jun 2021

Keywords

  • Acidovorax
  • Anaerobic catabolic pathways
  • Denitrifying bacteria
  • Di-(2-ethylhexyl) phthalate
  • Endocrine disruptor
  • Metagenomics
  • Phthalate esters

ASJC Scopus subject areas

  • Microbiology
  • Ecology, Evolution, Behavior and Systematics
  • Biochemistry
  • Physiology
  • Modelling and Simulation
  • Molecular Biology
  • Genetics
  • Computer Science Applications

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