Degradation of 17beta-estradiol by a gram-negative bacterium isolated from activated sludge in a sewage treatment plant in Tokyo, Japan

Abstract

A 17beta-estradiol (E2)-degrading bacterium was isolated from activated sludge in a sewage treatment plant in Tokyo, Japan. The isolate was suggested to be a new Novosphingobium species. Gas chromatography-mass spectrometry and (1)H nuclear magnetic resonance analyses of the metabolites of E2 degradation suggested that no toxic products accumulated in the culture medium.

FIG. 1.

Typical time courses for the degradation of E2 by the strain ARI-1. Degradation of 30, 10, or 5 mg of E2 in 30 ml of medium is indicated by open circles, concentric circles, or solid circles, respectively.

FIG. 2.

Total ion chromatograms of the chloroform extracts of 0 (A)- and 30 (B)-day-old cultures. The E2 peaks are indicated by arrowheads.

FIG. 3.

NMR spectra of the chloroform extracts of 0 (A)- and 30 (B)-day-old cultures. Each numbered proton signal in panel A corresponds to a position in the structure of E2 as shown in panel C. The asterisk indicates signals of methylene protons (positions 6, 7, 11, 12, 15, and 16 in E2) and methine protons (positions 8, 9, and 14 in E2). Signals at 3.3 and 4.9 ppm are derived from the solvent (CD₃OD and HDO, respectively).