Mycobacteriaceae Mineralizes Micropolyethylene in Riverine Ecosystems

Xiaoxu Sun, Zhenyu Chen, Tianle Kong, Zheng Chen, Yiran Dong, Max Kolton, Zhiguo Cao, Xin Zhang, Haihan Zhang, Guoqiang Liu, Pin Gao, Nie Yang, Ling Lan, Yating Xu, Weimin Sun

Research output: Contribution to journalArticlepeer-review

Abstract

Microplastic (MP) contamination is a serious global environmental problem. Plastic contamination has attracted extensive attention during the past decades. While physiochemical weathering may influence the properties of MPs, biodegradation by microorganisms could ultimately mineralize plastics into CO2. Compared to the well-studied marine ecosystems, the MP biodegradation process in riverine ecosystems, however, is less understood. The current study focuses on the MP biodegradation in one of the world's most plastic contaminated rivers, Pearl River, using micropolyethylene (mPE) as a model substrate. Mineralization of 13C-labeled mPE into 13CO2provided direct evidence of mPE biodegradation by indigenous microorganisms. Several Actinobacteriota genera were identified as putative mPE degraders. Furthermore, two Mycobacteriaceae isolates related to the putative mPE degraders, Mycobacterium sp. mPE3 and Nocardia sp. mPE12, were retrieved, and their ability to mineralize 13C-mPE into 13CO2was confirmed. Pangenomic analysis reveals that the genes related to the proposed mPE biodegradation pathway are shared by members of Mycobacteriaceae. While both Mycobacterium and Nocardia are known for their pathogenicity, these populations on the plastisphere in this study were likely nonpathogenic as they lacked virulence factors. The current study provided direct evidence for MP mineralization by indigenous biodegraders and predicted their biodegradation pathway, which may be harnessed to improve bioremediation of MPs in urban rivers.

Original languageEnglish
Pages (from-to)15705-15717
Number of pages13
JournalEnvironmental Science & Technology
Volume56
Issue number22
DOIs
StatePublished - 15 Nov 2022

Keywords

  • Mycobacterium
  • Nocardia
  • microplastic
  • pangenomic analysis
  • polyethylene biodegradation

ASJC Scopus subject areas

  • Chemistry (all)
  • Environmental Chemistry

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