LEQUIA, Institute of the Environment, University of Girona, Campus Montilivi, E-17071 Girona, Catalonia, Spain.
Chemosphere. 2013 Sep;93(1):99-106. doi: 10.1016/j.chemosphere.2013.04.094. Epub 2013 May 29.
The bacterial community shift on a lab scale Sequencing Batch Reactor (SBR) fed with synthetic wastewater and exposed to 50μgL(-1) of sulfamethoxazole (SFX) for 2months was investigated in this study. The impact on biological nutrient removal performance and SFX removal efficiencies were also studied. Satisfactory biological nutrient removal was observed as regards to COD and Nitrogen. SFX removal efficiencies ranged between 20% and 50% throughout the experimental period, enhanced within the aerobic phases of the SBR cycle, with no evident signs of biomass acclimation. Nevertheless, denaturing gradient gel electrophoresis (DGGE) analysis showed significant variance leading to not only the fading, but also the emergence of new species in the bioreactor bacterial community after SFX dosage. According to the phylogenetic analysis, bacteria belonging to Betaproteobacteria and Gammaproteobacteria classes were the dominant species, among them, the Thiotrix spp. (Gammaproteobacteria) cell number increased due to its tolerance to the antibiotic. On the other hand, the classes Sphingobacteria, Actinobacteria, Chloroflexi and Chlorobi were found to be more vulnerable to the antibiotic load and disappeared. The sulphonamide resistance gene sulI was also quantified and discussed, as there are very few studies on bacterial resistance in lab-scale treatment reactors.
本研究考察了在实验室规模序批式反应器（SBR）中，以合成废水为底物并暴露于 50μgL(-1)的磺胺甲恶唑（SFX）下 2 个月后，细菌群落的变化。还研究了其对生物脱氮性能和 SFX 去除效率的影响。该 SBR 对 COD 和氮的生物脱氮效果良好。SFX 的去除效率在整个实验期间介于 20%至 50%之间，在 SBR 周期的好氧相中增强，生物量没有明显的适应迹象。然而，变性梯度凝胶电泳（DGGE）分析显示出显著的变化，导致磺胺甲恶唑投加后生物反应器细菌群落不仅消失，而且还出现了新的物种。根据系统发育分析，属于β变形菌纲和γ变形菌纲的细菌是优势物种，其中，硫杆菌属（γ变形菌纲）的细胞数量增加，因为其对该抗生素具有耐受性。另一方面，发现鞘脂杆菌门、放线菌门、绿弯菌门和绿菌门等类群对抗生素负荷更为敏感，因此消失了。磺胺类抗性基因 sulI 也被定量并进行了讨论，因为在实验室规模处理反应器中，关于细菌抗性的研究很少。
