REVIEW article
Front. Microbiol.
Sec. Microbiotechnology
Volume 16 - 2025 | doi: 10.3389/fmicb.2025.1630636
This article is part of the Research TopicGreen and Sustainable Remediation: Advances in Microbial Technologies for Legacy and Emerging ContaminantsView all articles
Diversity of Estrogen Biodegradation Pathways and Application in Environmental Bioremediation
Provisionally accepted
- 1University of Bahrain, Manama, Bahrain
- 2Centre of Environmental and Biological Studies, Arabian Gulf University, Manama, Bahrain
- 3Biodiversity Research Center, Academia Sinica, Taipei, Taiwan, Taipei, Taiwan
- 4Biodiversity Research Center, Academia Sinica, Taipei, Taiwan, tai, Taiwan
- 53Biodiversity Research Center, Academia Sinica, Taipei, Taiwan, taipei, Taiwan
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Steroid estrogens, including the naturally occurring hormones estrone (E1), estradiol (E2), and estriol (E3), as well as the synthetic estrogen ethinylestradiol (EE2), play essential physiological roles in the regulation of the reproductive systems and development of secondary sex characteristics in humans and animals. Environmental pollution with steroid estrogens is gaining rising concerns worldwide due to their endocrine-disrupting and carcinogenic properties, which can harm humans and aquatic organisms. Hence, efficient removal of these compounds, particularly from wastewater, is deemed key to prevent environmental pollution with estrogens. Although several physicochemical treatments contribute to estrogen elimination from wastewater treatment plants (WWTPs), biological treatment via microbial biodegradation remains the most efficient estrogen removal approach. Several estrogen-degrading/transforming bacteria were isolated mainly from activated sludge samples collected from WWTPs. Moreover, biochemical, and molecular aspects for estrogen degradation pathways were revealed recently for estrone and estradiol. On the contrary, less knowledge is currently available for E3 and EE2 biodegradation pathways. Despite high structural similarity among steroid estrogens, they can be degraded via a diversity of biodegradation and biotransformation pathways. Nonetheless, these pathways exhibit common as well as unique biochemical and molecular features. Moreover, steroid estrogens are interconvertible, which can affect their environmental concentrations, and hence, their persistence/biodegradability. In this review, we present and discuss the various steroid estrogen biodegradation and biotransformation pathways, with a focus on the biochemical aspects. Furthermore, we highlight some of the known abiotic estrogen reactions and the recent discoveries on microbial estrogenesis and envisage how they can affect estrogen susceptibility to microbial degradation.
Keywords: environment, wastewater, Estradiol, pollution, Endocrine-disrupting chemicals, 4,5-seco pathway
Received: 18 May 2025; Accepted: 08 Sep 2025.
Copyright: © 2025 Hashem, Ismail, Chiang and Bekhit. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Wael Ahmed Ismail, Centre of Environmental and Biological Studies, Arabian Gulf University, Manama, Bahrain
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