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

摘要:

【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(Gordonia sp.)。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。

关键词:邻苯二甲酸二乙基己基酯(DEHP)，微生物降解，gyrB基因，戈登氏菌属，邻苯二甲酸

Abstract:

[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, physiological 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 temperature 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-NH1was 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.

Key words:Di(2-ethylhexy) phthalate (DEHP), Microbial degradation, gyrB gene, Gordonia sp., Phthalic acid