International Postgraduate Programs in Environmental Management, Graduate School, Chulalongkorn University, Bangkok, Thailand.
J Hazard Mater. 2012 Jun 30;221-222:35-44. doi: 10.1016/j.jhazmat.2012.03.072. Epub 2012 Apr 3.
17α-Methyltestosterone (MT), a synthetic anabolic androgenic steroid, is widely used in aquafarming for the production of an all male fish population such as Nile tilapia. This study isolated, identified and characterized MT-degrading bacteria in the sediment and water from a masculinizing pond of Nile tilapia fry. Based on the phylogeny, physiological properties and cell morphology, the three isolated MT-degrading bacteria were related closely to Rhodococcus equi, Nocardioides aromaticivorans, and Nocardioides nitrophenolicus. Growth of the three isolated strains was found to be inhibited for MT concentrations in the range of 1.0-10mg/L. The inhibition of cell growth was found to be modeled using the Haldane's substrate inhibition model. The kinetic constants ranged from 0.13 to 0.19h(-1) for μ(max), 0.7-24.8mg/L for K(s) and 19.6-76.2mg/L for K(i). Androgenic activity using β-galactosidase assay showed that all strains degraded MT to the products with no androgenic potency.
17α-甲基睾丸酮（MT）是一种合成的同化雄性甾体激素，广泛用于水产养殖中，用于生产全雄性鱼类种群，如尼罗罗非鱼。本研究从雄性化尼罗罗非鱼鱼苗池塘的沉积物和水中分离、鉴定和表征了 MT 降解细菌。根据系统发育、生理特性和细胞形态，这三种分离的 MT 降解菌与马红球菌、芳香诺卡氏菌和硝化诺卡氏菌密切相关。发现这三种分离株的生长受到 1.0-10mg/L 范围内 MT 浓度的抑制。发现细胞生长的抑制可以用 Haldane 的底物抑制模型来模拟。动力学常数的范围为 0.13-0.19h(-1)用于μ(max)，0.7-24.8mg/L 用于 K(s)和 19.6-76.2mg/L 用于 K(i)。使用β-半乳糖苷酶测定法的雄激素活性表明，所有菌株都将 MT 降解为无雄激素活性的产物。
