两株邻苯二甲酸二丁酯降解菌的分离鉴定及降解特性的研究

Isolation and Characterization of Two Di-n-butyl phthalate Degrading Bacteria

采用水-硅油双相体系从污染土壤中驯化分离到2株能够以邻苯二甲酸二丁酯(DBP)为惟一碳源和能源生长的菌株TS2H、TS2L,经过形态特征、生理生化以及16SrDNA序列分析,菌株分别鉴定为乙酸钙不动杆菌属(Acinetobacter calcoaceticus)和铜绿假单胞菌(Pseudomonas aeruginosa),对其降解DBP的特性进行了研究,探讨了可能的生物降解途径。结果表明,菌株TS2H、TS2L在48h内对40mg·L-1初始浓度DBP的降解率分别达到98.64%、74.62%,TS2H降解DBP的中间代谢产物主要有邻苯二甲酸以及一些小分子酸类和醇类物质。

Di-n-butyl phthalate （DBP） is one of the phthalate esters （PAEs） used extensively in the manufacture of plastics and contributes to the environmental pollution. Bioremediation is regarded as an alternative method to remove PAEs from the contaminated sites. In this study, two bacteria named TS2H and TS2L, respectively, were isolated from the polluted vegetable farm soils with water-silicon oil biphasic systems. Both the two bacteria could use DBP as a sole source of carbon and energy and their degrading DBP characteristics were studied. The traditional morphology, physiological-biochemical properties as well as 16S rDNA gene sequence analysis were applied to the bacteria classification. The strain TS2H and TS2L were identified as Acinetobacter calcoaceticus and Pseudomonas aeruginosa, respectively. The strain TS2H showed a high tolerance to DBP as it could grow well in the medium containing 40 mg·L^-1 DBP and the degradation rate reached 98.64% within 48 h, while the degradation rate of strain TS2L presented 74.62% under the same condition. The DBP intermediate metabolites of pure culture TS2H were determined by mass spectrometry, and 1,2-Benzenedicarboxylic acid was identified as the major metabolite, and some low molecular acids and alcohols were also detected.