一株高效DEHP降解菌的分离、鉴定及其降解特性

Isolation and characterization of a highly efficient DEHP-degrading bacterium

【目的】分离得到高效的邻苯二甲酸二乙基己基酯(DEHP)降解菌。【方法】采用富集培养法筛选分离菌株,并对菌株进行驯化;通过PCR扩增得到其16S rRNA和gyrB基因序列,进行同源序列分析及分子系统发育树的构建,同时结合形态学观察和生理生化实验对菌株进行初步鉴定;采用高效液相色谱(HPLC)分析菌株对DEHP的降解特性。【结果】分离得到一株能以DEHP为唯一碳源和能源生长的菌株,命名为HS-NH1,初步鉴定其为戈登氏菌(Gordoniasp.)。菌株HS-NH1最适的生长和降解条件为30°C、pH 7.0,在此条件下,该菌株60 h内能够将浓度为500 mg/L的DEHP降解90%以上。高效液相色谱(HPLC)分析表明,菌株HS-NH1在降解DEHP过程中产生了一种重要的中间代谢产物——邻苯二甲酸。底物广谱性试验证明,菌株HS-NH1能够有效地利用多种常见的邻苯二甲酸酯(PAEs)与芳香族衍生物。【结论】筛选得到了一株DEHP降解菌Gordonia sp.HS-NH1,该菌降解效率高,具有良好的底物广谱性,在邻苯二甲酸酯类化合物的污染治理中将会有一定的应用潜力。

[Objective] We isolated and identified di（2-ethylhexy） phthalate-degrading strains. [Methods] We isolated and domesticated the strain by gradient enrichment culture. We identified the strain by 16S rRNA gene and gyrB gene sequence analysis, combined with morphological, physio- logical and biochemical characterization. And we analyzed the degradation characteristics of the strain using High Performance Liquid Chromatography （HPLC）. [Results] A strain （named HS-NH1） with DEHP-degrading activity was obtained and identified as Gordonia sp.. The optimum tempera- ture and pH for growth and degradation of Gordonia sp. HS-NH1 were 30 ~C and 7.0 respectively, strain HS-NH1 was able to almost degrade 500 mg/L di（2-ethylhexy） phthalate to above 90% within 60 hours. One of the major metabolites of di（2-ethylhexy） phthalate degradation were identified as phthalic acid by HPLC. A substrate utilization test showed that HS-NHlwas also able to utilize many other common phthalates. [Conclusion] A bacterial strain with a high di（2-ethylhexy） phtha- late-degrading efficiency was obtained, and the strain may have a potential application in dealing with the pollution caused by phthalate esters.