雌二醇降解菌的筛选鉴定及降解特性研究

Screening and Characterization of Estradiol-degrading Bacteria and Their Degradation Properties

为了实现烟草薄片废水中雌激素的生物降解,以高浓度雌二醇(Estradiol,E2)为唯一碳源,从烟草废水进水处的污泥中筛选到一株优势降解菌,在分离平板上呈乳白色、圆润、有光泽,菌落直径0.1~0.5 mm左右,革兰氏染色为阴性,16S rRNA鉴定为假单胞菌(Pseudomonas sp.CO03)。在单因素试验的基础上,以E2的降解率为响应值,采用Box-Benhnken实验设计及响应面分析法对降解过程中的温度、pH、底物浓度进行优化。结果表明:温度对E2降解率影响最大,E2浓度次之,pH影响最小;降解E2的最优条件为:温度37℃、pH值7.0、E2浓度5.5 mg/L,以此参数测定E2的降解率为81.67%。将该菌株应用于烟草浓缩液和烟草薄片废水进水口E2的降解,7d后E2的降解率分别为31.21%、53.14%。研究获得的高效降解菌对E2降解能力强,效率高,可用于烟草薄片废水中雌激素的生物降解,对于甾体雌激素的降解及环境保护具有重要意义。

In order to achieve the biodegradation of estrogens in tobacco sheet wastewater,this study selected a dominant degrading strain from the sludge at the influent of tobacco wastewater,using high concentrations of estradiol(Estradiol,E2) as the sole carbon source.The strain appeared as creamy white,round,and shiny colonies on E2 agar plates,with a diameter of approximately 0.1-0.5 mm,and was identified as a Gram-negative bacterium through 16S rRNA analysis,designated as Pseudomonas sp.CO03.Based on single-factor experiments,with the degradation rate of E2 as the response value,the temperature,pH,and substrate concentration during the degradation process were optimized using the Box-Benhnken experimental design and response surface analysis method.The results indicated that temperature had the greatest impact on the E2 degradation rate,followed by E2 concentration,with pH having the least effect.The optimal conditions for degrading E2 were determined to be:a temperature of 37 ℃,a pH value of 7.0,and an E2 concentration of 5.5 mg/L,under which the degradation rate of E2 was measured to be 81.67%.When this strain was applied to the degradation of E2 in tobacco concentrate and at the influent of tobacco wastewater,the degradation rates of E2 after 7 days were 31.21% and 53.14%,respectively.The highly efficient degrading strain obtained from this study has a strong ability and high efficiency for E2 degradation,which can be used for the biodegradation of estrogens in tobacco sheet wastewater,and is of significant importance for the degradation of steroidal estrogens and environmental protection.