摘要:
为探究环境浓度抗生素(5μg·L-1和50μg·L-1)选择性压力下活性污泥微生物的性能变化,选择四环素及磺胺甲噁唑2种高频检出的抗生素作为研究对象,分别考察2种抗生素单一和复合作用下对序批式活性污泥反应器(SBR)中废水处理效能、微生物活性及群落结构的影响。结果表明,与不添加抗生素的空白对照组相比,2种抗生素在50μg·L-1和5μg·L-1暴露浓度下,经过60 d运行,COD和NH4+-N去除效果未受明显影响(P>0.05),微生物的活菌比变化不显著(P>0.05),ATP含量显著降低(P<0.05)。在微生物群落结构方面,革兰氏阳性菌增加,革兰氏阴性菌减少,原生动物含量减少,香农-威尔生物多样性指数下降。添加抗生素的样品中微生物优势菌群由变形菌门变为放线菌门,放线菌含量(均高于45%),高于空白对照组(30.72%);放线菌门的Micropruina属所占比例最高(>24%),且高于空白对照组(18.77%)。抗生素选择性压力可改变活性污泥微生物的活性及群落结构,但长期作用下对污水处理效能及抗生素抗性基因传播的影响还需要进一步研究。
Abstract:
To investigate the change of wastewater treatment efficiency, microbial activity and community composition under antibiotic selected pressure, a lab scale Sequencing Batch Reactor (SBR) fed with synthetic water was exposed to tetracycline (TC) and/or sulfamethoxazole (SMX) with both 50 μg·L-1 and 5 μg·L-1, respectively. Results showed that COD and NH4+ -N removal appeared substantially unchanged after 60 d under the antibiotic exposure (P>0.05). The microbial activity analysis showed that the ratio of live bacteria changed little, but ATP concentration decreased significantly (P<0.05) under antibiotic selection pressure. Results of microbial community composition indicated that gram-positive bacteria increased, while gram-negative bacteria and protozoa decreased, as well as PLFA Shannon-Wiener diversity decreased after exposure to antibiotics. Actinobacteria was the dominant phylum (>45%) while Proteobacteria was dominant without addition of antibiotics (30.72%). Micropruina belonging to Actinobacteria phylum were the dominant species (>24%). The microbial activity and community composition of activated sludge can be affected by antibiotic selected pressure. Further and systematic studies on the long-time effect on the wastewater treatment efficiency and spread of antibiotic resistance genes are strongly recommended.
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