摘　要：为了获得邻苯二甲酸酯（PAEs）生物降解菌，从农田土壤筛选出一株能够以PAEs为唯一碳源和能源生长的微生物，命名为SD2。采用聚合酶链式反应（PCR）扩增得到其16S rDNA并构建分子系统发育树，可鉴定出其为冢村菌（Tsukamurella）。研究该菌株在不同的温度、pH值和转速条件下对邻苯二甲酸二丁酯（DBP）的降解情况，同时采用高效液相色谱（HPLC）测定该菌株对DBP的降解能力。结果表明，SD2对DBP的最佳降解条件为：温度为30℃，pH值为9，转速为150 r/min。在该最佳条件下，SD2在72 h内可以完全降解500 mg/L的DBP。底物广谱试验表明，该菌能够降解长短链的PAEs化合物及常见的代谢产物。同时采用气相质谱联用仪（GC-MS）检测发现，DBP在降解的过程中产生了中间代谢产物邻苯二甲酸丁基甲酯和邻苯二甲酸（PA），预示着该菌具备完全降解DBP的能力。这是首次关于冢村菌降解PAEs污染物的报道，能够为PAEs污染环境的生物降解及修复提供新的微生物资源。
关键词：冢村菌；邻苯二甲酸二丁酯；生物降解；16S rDNA；有机污染物
中图分类号：S154.3　　　　　　 文献标志码：A　　　　　　 DOI: 10.3969/j.issn.1007-7146.2020.06.013

Abstract: In order to obtain phthalic acid esters (PAEs) biodegradation strain, a bacterial strain capable of growing with PAEs as the sole carbon source and energy was selected from contaminated soil and named as SD2. The 16S rDNA obtained by PCR amplification and the construction of molecular phylogeny trees can be identified as Tsukamurella sp. The degradation of DBP under different temperature, pH value, and rotational speed conditions was investigated. The degradation ability of the strain to DBP was determined by high performance liquid chromatography. The results showed that the optimum degradation condition of SD2 is temperature of 30℃, pH value of 9 and rotational speed of 150 r/min. Under this optimum condition, SD2 can completely degrade 500 mg/L DBP within 72 h. The intermediate metabolites, butylmethyl phthalate and phthalic acid, were detected by GC-MS during the degradation of DBP, and phthalic acid could be further completely degraded into CO2 and H2O. To our knowledge, this is the first report about the biodegradation of PAEs by genus Tsukamurella.
Key words: Tsukamurella; dibutyl phthalate; biodegradation; 16S rDNA; organic pollutants