Biodegradation of estrogen conjugates by bacteria isolated from river sediments

Area of Science:

• Environmental Microbiology
• Biochemistry

Background:

• Estrogen conjugates are prevalent environmental contaminants.
• Understanding their biodegradation is crucial for ecological risk assessment.

Purpose of the Study:

• To investigate the capacity of E. coli from river sediments to degrade estrogen conjugates.
• To compare the degradation efficiency of isolated E. coli with a pure strain and sediment extracts.

Main Methods:

• Batch biodegradation experiments were conducted.
• Tested glucuronide estrogens (E1-GLU, E2-GLU, E3-GLU) using E. coli, non-E. coli bacteria, and sediment crude extracts.
• Enzyme activity was compared using a pure E. coli strain (KCTC 2571).

Main Results:

• E. coli from sediments and the pure strain (KCTC 2571) exhibited similar degradation trends for estrogen conjugates.
• Fecal bacteria demonstrated a high deconjugation rate, cleaving ~50% of glucuronide moieties within 4 hours.
• Sediment crude extracts showed slower degradation, with incomplete estrogen conjugate breakdown after 12 hours.

Conclusions:

• E. coli plays a significant role in the environmental biodegradation of estrogen conjugates.
• Fecal bacteria possess a notable capacity for cleaving glucuronide estrogens.
• These findings enhance understanding of estrogen fate and behavior mediated by bacteria in aquatic environments.