Removal of estrone, 17β-estradiol, and estriol from sewage and cow dung by immobilized Novosphingobium sp. ARI-1
2018
Liu, Juan | Li, Shunyao | Li, Xin | Gao, Yanzheng | Ling, Wanting
Immobilized bacterial agents (IBA) can increase the cell density and improve the environmental adaptability of bacteria. An estrogen-degrading bacterium, Novosphingobium sp. ARI-1, was immobilized in calcium alginate (CA) using an embedding method and applied to the removal of estrogens from natural sewage and cow dung. The optimum immobilization conditions were as follows: sodium alginate (SA) and CaCl₂·2H₂O concentrations of 5% (m/v) and 4% (m/v), respectively; a bacterial suspension to SA ratio of 1:2; and cross-linking for 6 h at 4°C. Immobilized strain ARI-1 mediated the biodegradation of estrone (E1), 17β-estradiol (E2), and estriol (E3) either individually or in combination and was tolerant of various temperatures and pH values. Immobilized ARI-1 removed 80.43%, 94.76%, and 100% of E1, E2, and E3 from sewage containing 1.75, 0.71, and 1.52 μg L⁻¹ of the three test estrogens within seven days, respectively. In cow dung containing initial E1, E2, and E3 concentrations of 0.71, 0.64, and 0.66 mg kg⁻¹, respectively, E1 and E2 concentrations were below the limit of detection, and 1.09% of E3 remained after incubation with immobilized ARI-1 for seven days. These results confirmed the utility of immobilized strain ARI-1 for the removal of estrogens from environmental matrices.
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