Isolation and Characterization of Aerobic and Facultative Anaerobic 17β-Estradiol Degrading Bacteria in Paddy Soils and Their Potential Mechanisms.

17β-estradiol (E2) contamination resulting from the widespread use of animal manure poses a new threat to the agricultural environment. Since anaerobic environments have been reported to significantly extend the persistence of E2, estrogen pollution of anaerobic farmland soils (e.g., paddy soils) is of particular concern, necessitating the development of in situ high-efficiency E2 bioremediation microorganisms. In this work, six E2-degrading strains were isolated from paddy soils, including strains from , , , , , and . Among these strains, sp. AEPI-SP11 and sp. AEPI-SP17 were able to degrade over 90% of 20 mg/L E2 within 5 days. Although both AEPI-SP11 and AEPI-SP17 exhibited strong tolerance to pH, temperature, and initial E2 concentrations (2, 5, 20, and 50 mg/L), only AEPI-SP17 was capable of biodegrading E2 under anaerobic conditions. Based on genomic analysis, we further obtained the whole genome sequences of AEPI-SP11 and AEPI-SP17 and identified and compared potential genes responsible for estrogen degradation in the two strains. Overall, this work significantly enhances our understanding of E2-degrading strains in paddy soils, offers valuable insights into the degradation mechanisms under varying conditions, and provides potential microbial resources for the effective control of E2 pollution in farmlands.