一株DMP降解菌的分离鉴定及其降解特性

Isolation,Identification and Degradation Characteristics of a DMP-degrading Strain

从山东省潍坊市污染河流底泥中筛选到1株能够以酞酸酯(Phthalic acid esters,PAEs)为唯一碳源和能源生长的微生物,命名为JDC-3,根据形态学观察、生理生化指标测定和分子生物学鉴定结果,将该菌株初步鉴定为戴尔福特菌属(Delftia sp.),以一对简并引物,首次在该属中扩增出编码邻苯二甲酸双加氧酶的基因片段。同时以邻苯二甲酸二甲酯(Dimethyl phthalate,DMP)为目标测试物,利用高效液相色谱(HPLC)测定了JDC-3的降解性能,得出该菌对DMP降解的最佳条件为:pH7.0～8.0、温度30°C～35°C;在不同DMP初始浓度下研究了该菌的降解动力学,结果表明当浓度低于300mg/L时的降解动力学方程为ln C=-0.06837t+A,半衰期为12.48h,当初始浓度不断增加,DMP对JDC-3的抑制能力增强,JDC-3对DMP的降解速率不断下降,半衰期增大。

A bacterial strain which could grow well on the substrate of PAEs as the sole source of carbon and energy was isolated from contaminated sludge in the river of WeiFang in ShangDong province and it was designated as JDC-3. Based on the morphology, biophysical and biochemical properties as well as molecular characteristics, this isolate was preliminarily identified as Delftia sp.. A fragment of phthalate dioxygenase gene was successfully amplified from the genus of Delftia for the first time using a set of degenerate primers. Meanwhile, the degradation capability of JDC-3 was determined by HPLC using DMP as test sub- strate. The results showed that the optimal pH and temperature were at 7.0-8.0 and 30℃-35℃ respectively. The degradation kinetics of JDC-3 was studied in different initial DMP concentration under optimal conditions. The results indicated that the degradation dynamic equation was In C = - 0.06837 t ＋ A when DMP concentration was lower than 300 mg/L, with half life of 12.48 h. The degradation rate decreased and half life of JDC-3 prolonged as the initial concentration kept on increasing.