Harnessing microbial phylum-specific molecular markers for assessment of environmental estrogen degradation
Journal
Science of the Total Environment
Journal Volume
896
Date Issued
2023
Author(s)
Hsiao, Tsun-Hsien
Chen, Po-Hao
Wang, Po-Hsiang
Brandon-Mong, Guo-Jie
Li, Chen-Wei
Horinouchi, Masae
Hayashi, Toshiaki
Ismail, Wael
Meng, Menghsiao
Chiang, Yin-Ru
Abstract
Steroidal estrogens are ubiquitous contaminants that have garnered attention worldwide due to their endocrine-disrupting and carcinogenic activities at sub-nanomolar concentrations. Microbial degradation is one of the main mechanisms through which estrogens can be removed from the environment. Numerous bacteria have been isolated and identified as estrogen degraders; however, little is known about their contribution to environmental estrogen removal. Here, our global metagenomic analysis indicated that estrogen degradation genes are widely distributed among bacteria, especially among aquatic actinobacterial and proteobacterial species. Thus, by using the Rhodococcus sp. strain B50 as the model organism, we identified three actinobacteria-specific estrogen degradation genes, namely aedGHJ, by performing gene disruption experiments and metabolite profile analysis. Among these genes, the product of aedJ was discovered to mediate the conjugation of coenzyme A with a unique actinobacterial C17 estrogenic metabolite, 5-oxo-4-norestrogenic acid. However, proteobacteria were found to exclusively adopt an α-oxoacid ferredoxin oxidoreductase (i.e., the product of edcC) to degrade a proteobacterial C18 estrogenic metabolite, namely 3-oxo-4,5-seco-estrogenic acid. We employed actinobacterial aedJ and proteobacterial edcC as specific biomarkers for quantitative polymerase chain reaction (qPCR) to elucidate the potential of microbes for estrogen biodegradation in contaminated ecosystems. The results indicated that aedJ was more abundant than edcC in most environmental samples. Our results greatly expand the understanding of environmental estrogen degradation. Moreover, our study suggests that qPCR-based functional assays are a simple, cost-effective, and rapid approach for holistically evaluating estrogen biodegradation in the environment. © 2023 The Authors
Subjects
Actinobacteria
Coenzyme A ligase
Endocrine-disrupting chemicals
Estrogen biodegradation
Proteobacteria
α-oxoacid ferredoxin oxidoreductase
Type
journal article