[Isolation, identification of 17beta-estradiol (E2)-degrading strain and its degradation characteristics]

A novel bacterium capable of degrading 17beta-estradiol (E2) was isolated from the activated sludge collected from wastewater treatment plant of an oral contraceptives producing factory in Xianju, Zhejiang. According to its morphology, physiochemical characteristics and 16S rDNA sequence analysis, this strain was identified as Bacillus sp. The optimal pH and temperature for E2 biodegradation in shaking flasks were 7.5 and 30 degrees C, respectively. The enhanced action of peptone and Lab-Lemco were quite obvious; metal ions such as Ba2+, Zn2+, Sn2+, Cd2+, Cr2+, Pb2+ inhibited degradation, and the actions were ordinal increasing; the addition such as Ca2+, Fe2+, KNO and amylum had no obvious effect on the degradation of E2. Furthermore, this strain could degrade E2 completely within 7 days with initial concentration ranged from 0.5 to 50 mg/L and was capable of converting E2 to estrone (E1), then to nonestrogenic compounds, thus 95% of initial estrogenic activities was decreased within 15 days during the biodegradation process.