Mechanistic and phylogenetic insights into actinobacteria-mediated oestrogen biodegradation in urban estuarine sediments

Tsun Hsien Hsiao, Yi Lung Chen, Menghsiao Meng, Meng Rong Chuang, Masae Horinouchi, Toshiaki Hayashi, Po Hsiang Wang*, Yin Ru Chiang*

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

11 Scopus citations


Steroidal oestrogens are often accumulated in urban estuarine sediments worldwide at microgram per gram levels. These aromatic steroids have been classified as endocrine disruptors and group 1 carcinogens. Microbial degradation is a naturally occurring mechanism that mineralizes oestrogens in the biosphere; however, the corresponding genes in oestrogen-degrading actinobacteria remain unidentified. In this study, we identified a gene cluster encoding several putative oestrogen-degrading genes (aed; actinobacterial oestrogen degradation) in actinobacterium Rhodococcus sp. strain B50. Among them, the aedA and aedB genes involved in oestrogenic A-ring cleavage were identified through gene-disruption experiments. We demonstrated that actinobacterial oestrone 4-hydroxylase (AedA) is a cytochrome P450-type monooxygenase. We also detected the accumulation of two extracellular oestrogenic metabolites, including pyridinestrone acid (PEA) and 3aα-H-4α(3'-propanoate)-7aβ-methylhexahydro-1,5-indanedione (HIP), in the oestrone-fed strain B50 cultures. Since actinobacterial aedB and proteobacterial edcB shared < 40% sequence identity, 4-hydroxyestrone 4,5-dioxygenase genes (namely aedB and edcB) could serve as a specific biomarker to differentiate the contribution of actinobacteria and proteobacteria in environmental oestrogen degradation. Therefore, 4-hydroxyestrone 4,5-dioxygenase genes and the extracellular metabolites PEA and HIP were used as biomarkers to investigate oestrogen biodegradation in an urban estuarine sediment. Interestingly, our data suggested that actinobacteria are active oestrogen degraders in the urban estuarine sediment.

Original languageEnglish
Pages (from-to)1212-1227
Number of pages16
JournalMicrobial Biotechnology
Issue number3
StatePublished - 05 2021
Externally publishedYes

Bibliographical note

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© 2021 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.


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