邻苯二甲酸酯降解菌的分离鉴定及降解特性

Isolation and identification of phthalate-degrading bacteria and their characteristics

摘要:

为了对邻苯二甲酸酯(PAEs)污染的土壤进行生物修复,从人工湿地土壤样品中分离到7株能够以PAEs为唯一碳源和能源生长的菌株D1～D7,对其综合形态特征、主要生理生化特性和16S rRNA基因序列分析结果进行鉴定,并通过3 d摇瓶间歇试验检测其对PAEs和邻苯二甲酸(PA)的降解能力．结果表明,D1、D2与假单胞菌属(Pseudomonas sp.)的同源性分别为100％和98％,D3与肠杆菌属(Enterobacter sp.)的同源性在99％以上,其余4株细菌与红球菌属(Rhodococcus sp.)的同源性都在98％以上．这些菌株对邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二乙酯(DEP)和邻苯二甲酸二异辛酯(DEHP)的降解率分别在65％,60％和30％以上,且对PAEs的降解率随侧链烷基链的增长而下降．这7株PAEs降解菌均能在以PAEs的降解中间产物——PA为唯一碳源的培养液中生长,对PA的利用率在18％～39％,这说明它们可能通过PA途径实现PAEs的完全降解．

Abstract:

In order to implement the bioremediation on the phthalate contaminated soil, seven bacteria strains D1-D7, which can use phthalate mixtures as the sole source of carbon and energy, were isolated from constructed wetland soil. The morphological, physiological and biochemical characteristics of the strains were studied. Strains D1 and D2 were identified as Pseudomonas sp., strain D3 as Enterobacter sp., the others as Rhodococcus sp., based on the 16S rRNA gene sequence analysis. The batch test results showed that all of the strains could degrade phthalate in three days effectively, the degradation efficiencies of DMP, DBP and DEHP were above 65％, 60％ and 30％ respectively. The degradation efficiency decreased with the increasing of phthalate alkyl chain length. The D1-D7 strains all grew with phthalic acid as the sole source of carbon and energy. The utilization of phthalic acid was 18％-39％, which showed that the phthalate could be thoroughly degraded by strains D1-D7 through phthalic acid metabolism pathway.