Biochemical Mechanisms and Catabolic Enzymes Involved in Bacterial Estrogen Degradation Pathways

Yi Lung Chen, Chang Ping Yu, Tzong Huei Lee, King Siang Goh, Kung Hui Chu, Po Hsiang Wang, Wael Ismail, Chao Jen Shih, Yin Ru Chiang

Research output: Contribution to journalArticlepeer-review

61 Scopus citations


Estrogens have been classified as group 1 carcinogens by the World Health Organization and represent a significant concern given that they are found in surface waters worldwide, and long-term exposure to estrogen-contaminated water can disrupt sexual development in animals. To date, the estrogen catabolic enzymes and genes remain unknown. Using a tiered functional genomics approach, we identified three estrogen catabolic gene clusters in Sphingomonas sp. strain KC8. We identified several estrone-derived compounds, including 4-hydroxyestrone, a meta-cleavage product, and pyridinestrone acid. The yeast-based estrogen assay suggested that pyridinestrone acid exhibits negligible estrogenic activity. We characterized 17β-estradiol dehydrogenase and 4-hydroxyestrone 4,5-dioxygenase, responsible for the 17-dehydrogenation and meta-cleavage of the estrogen A ring, respectively. The characteristic pyridinestrone acid was detected in estrone-spiked samples collected from two wastewater treatment plants and two suburban rivers in Taiwan. The results significantly expand our understanding of microbial degradation of aromatic steroids at molecular level.

Original languageEnglish
Pages (from-to)712-724.e7
JournalCell Chemical Biology
Issue number6
StatePublished - 22 Jun 2017


  • C-metabolomics
  • biodegradation
  • ecophysiology
  • estrogen
  • extradiol dioxygenase
  • functional genomics
  • RNA-seq
  • Sphingomonas
  • steroid hormones


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