Estrogen degraders and estrogen degradation pathway identified in an activated sludge
Journal
Applied and Environmental Microbiology
Journal Volume
84
Journal Issue
10
Date Issued
2018
Author(s)
Fu, Han-Yi
Shih, Chao-Jen
Huang, Lina
Wang, Yu-Sheng
Ismail, Wael
Chiang, Yin-Ru
Abstract
The environmental release and fate of estrogens are becoming an increasing public concern. Bacterial degradation has been considered the main process for eliminating estrogens from wastewater treatment plants. Various bacterial isolates are reportedly capable of aerobic estrogen degradation, and several estrogen degradation pathways have been proposed in proteobacteria and actinobacteria. However, the ecophysiological relevance of estrogen-degrading bacteria in the environment is unclear. In this study, we investigated the estrogen degradation pathway and corresponding degraders in activated sludge collected from the Dihua Sewage Treatment Plant, Taipei, Taiwan. Cultivation-dependent and cultivation-independent methods were used to assess estrogen biodegradation in the collected activated sludge. Estrogen metabolite profile analysis revealed the production of pyridinestrone acid and two A/B-ring cleavage products in activated sludge incubated with estrone (1 mM), which are characteristic of the 4,5-seco pathway. PCR-based functional assays detected sequences closely related to alphaproteobacterial oecC, a key gene of the 4,5-seco pathway. Metagenomic analysis suggested that Novosphingobium spp. are major estrogen degraders in estroneamended activated sludge. Novosphingobium sp. strain SLCC, an estrone-degrading alphaproteobacterium, was isolated from the examined activated sludge. The general physiology and metabolism of this strain were characterized. Pyridinestrone acid and the A/B-ring cleavage products were detected in estrone-grown strain SLCC cultures. The production of pyridinestrone acid was also observed during the aerobic incubation of strain SLCC with 3.7 nM (1 μg/liter) estrone. This concentration is close to that detected in many natural and engineered aquatic ecosystems. The presented data suggest the ecophysiological relevance of Novosphingobium spp. in activated sludge. © 2018 American Society for Microbiology.
Subjects
Activated sludge; Biodegradation; Estrone; Meta-cleavage dioxygenase; Novosphingobium; Wastewater treatment plant
Other Subjects
Aquatic ecosystems; Biodegradation; Sewage pumping plants; Sewage treatment plants; Toxicity; Wastewater treatment; Water treatment plants; Activated sludge; Dioxygenases; Estrone; Novosphingobium; Wastewater treatment plants; Activated sludge process; activated sludge; bacterium; bioassay; biodegradation; chemical compound; cultivation; ecophysiology; enzyme; enzyme activity; estrogenic compound; metabolism; metabolite; oxic conditions; physiology; wastewater treatment plant; Taipei; Taiwan; Actinobacteria; Bacteria (microorganisms); Novosphingobium; Proteobacteria; bacterial protein; estrogen; estrone; analysis; bacterium; bioremediation; classification; genetics; isolation and purification; metabolism; metagenomics; microbiology; phylogeny; sewage; Taiwan; waste water; water pollutant; Bacteria; Bacterial Proteins; Biodegradation, Environmental; Estrogens; Estrone; Metabolic Networks and Pathways; Metagenomics; Phylogeny; Sewage; Taiwan; Waste Water; Water Pollutants, Chemical
Type
journal article