土壤微生物群落对多环芳烃污染土壤生物修复过程的响应

Response of Soil Microbial Community to the Bioremediation of Soil Contaminated with PAHs

采用聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)方法,研究了土壤微生物群落多样性对生物表面活性剂强化的植物-微生物联合修复多环芳烃(PAHs)污染土壤的响应.结果表明,细菌群落的Shannon-Weaver指数修复前为3.17,修复后为3.24～3.45,多样性整体呈上升趋势,其中以植物-菌根真菌-降解菌处理最高,但各处理间无显著差异(P>0.05).聚类分析结果显示,植物、植物-鼠李糖脂、植物-菌根真菌和植物-菌根真菌-鼠李糖脂这4个处理的群落相似度在90%以上,植物-降解菌处理与这4个处理群落结构最近,此外,植物-降解菌-鼠李糖脂、植物-降解菌-菌根真菌-鼠李糖脂群落相似度在80%以上.通过测序比对,DGGE图谱上优势及特征性条带分别为Bacillus、Pseudomonas、Acidobacteria、Sphingmonas、Rhodopseudomonas、Firmicutes和Methylocytaceae等,可能是与PAHs降解密切相关的种属.生物表面活性剂强化的植物-微生物联合修复污染土壤过程中,在提高PAHs生物有效性基础上,改变了土壤微生物群落结构和丰度,从而可以有效提高PAHs的降解率.

The diversity of bacterial community in soil contaminated with polycyclic aromatic hydrocarbons（PAHs） was investigated during the plant-microbe remediation enhanced by biosurfactant rhamnolips（RH）,using the polymerase chain reaction-denaturing gradient gel electrophoresis（PCR-DGGE） method.The results showed that Shannon-Weaver diversity index was only 3.17 before bioremediation,and increased to 3.24-3.45 after bioremediation,in particular,highest value was found in the treatment of alfalfa（AL） inoculated with arbuscular mycorrhizal fungi（AM） and PAHs-degrading bacteria（DB） among all the treatments.The clustering analysis showed that the similarities of soil bacterial community of AL,AL＋RH,AL＋AM and AL＋AM＋RH were above 90%.At the same time,the similarity of AL＋DB was much closer to those of the four treatments mentioned above.Additionally,when the bacterial communities of AL＋DB＋RH,AL＋DB＋AM and AL＋DB＋AM＋RH were grouped together,the similarities of these three treatments were also higher than 80%.By sequence alignment,it was found that the predominant and characteristic bands in DGGE patterns were closely related with PAHs-degrading bacteria,such as Bacillus,Pseudomonas,Acidobacteria,Sphingmonas,Rhodopseudomonas,Firmicutes,and Methylocytaceae.Application of rhamnolipids in plant-microbe bioremediation not only improved the bioavailability of PAHs,but also had a simultaneous influence on the diversity of soil bacterial community,resulting in the efficient promotion of PAHs removal from soils.