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

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.

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

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.