Fedi Stefano, Tremaroli Valentina, Scala David, Perez-Jimenez Josè R, Fava F, Young Lily, Zannoni Davide
Department of Biology, General Microbiology Unit, University of Bologna, 42 Irnerio, 40126 Bologna, Italy.
Res Microbiol. 2005 Mar;156(2):201-10. doi: 10.1016/j.resmic.2004.09.001. Epub 2004 Nov 11.
In this study, T-RFLP analysis was used to determine the structure and spatial distribution of the indigenous bacterial community of an actual-site PCB-contaminated soil treated in aerobic packed-bed loop reactors (PBLRs) in the absence or in the presence of a mixture of randomly methylated beta-cyclodextrins (RAMEB) at 0.5 or 1% w/w. RAMEB was found to significantly enhance the aerobic bioremediation of soil with effects that increased proportionally with the concentration at which it was applied. At the end of treatment (180 days), T-RFLP analysis of the soil samples collected from the top and bottom regions of the PBLRs showed a series of 50 single T-RFs. Remarkably, the number of T-RFs was significantly lower (13-22) in samples collected from different sections of the RAMEB-amended bioreactors with respect to equivalent samples collected from the RAMEB-free reactor. Cluster analysis based on the presence or the absence of T-RFs peaks revealed high similarity, inside each reactor, between the top and bottom parts of its soil bed. Soil samples collected at the top and bottom regions of the two bioreactors amended with RAMEB, clustered together while the equivalent samples of the bioreactor without RAMEB formed a separate cluster which was distantly related to the soil samples obtained from the parallel amended bioreactor. Notably, T-RFLP analyses combined with extensive sequencing of 16S rDNA allowed us to tentatively allocate a series of bacterial species corresponding to specific peaks of the T-RFLP profiles and to determine their phylogenetic affiliation.
在本研究中，采用末端限制性片段长度多态性（T-RFLP）分析方法，来确定在有氧填充床环流反应器（PBLR）中处理的实际场地多氯联苯污染土壤中土著细菌群落的结构和空间分布，该反应器在不存在或存在0.5%或1%（w/w）的随机甲基化β-环糊精（RAMEB）混合物的情况下运行。结果发现，RAMEB能显著增强土壤的好氧生物修复效果，且其效果随施用浓度的增加而成比例提高。在处理结束时（180天），对从PBLR顶部和底部区域采集的土壤样品进行T-RFLP分析，结果显示出一系列50个单一的末端限制性片段（T-RF）。值得注意的是，与从无RAMEB反应器采集的等效样品相比，从添加RAMEB的生物反应器不同部位采集的样品中，T-RF的数量显著减少（13 - 22个）。基于T-RF峰的有无进行的聚类分析表明，在每个反应器内部，其土壤床的顶部和底部之间具有高度相似性。在添加RAMEB的两个生物反应器顶部和底部区域采集的土壤样品聚集在一起，而未添加RAMEB的生物反应器的等效样品则形成了一个单独的聚类，该聚类与从平行添加RAMEB的生物反应器获得的土壤样品关系较远。值得注意的是，T-RFLP分析与16S rDNA的广泛测序相结合，使我们能够初步确定一系列与T-RFLP图谱特定峰相对应的细菌种类，并确定它们的系统发育归属。
