摘要
考察了磁性纳米铁(Fe3O4NPs)对厌氧颗粒污泥溶解性微生物产物(SMP)、疏松胞外聚合物(LB-EPS)、紧密胞外聚合物(TB-EPS)的影响,同时利用高通量测序技术对厌氧颗粒污泥内微生物群落结构的变化进行了分析.结果表明,在长期接触实验过程中,投加Fe3O4NPs的反应器对COD去除率为83.6%,与对照组相比降低了5.7%.对照组与实验组中厌氧颗粒污泥TB-EPS含量(以VSS计)分别为178.20 mg·g-1和138.24 mg·g-1,而SMP含量分别为34.88 mg·L-1和27.44 mg·L-1;同时投加Fe3O4NPs后,在LB-EPS三维荧光(EEM)光谱中,紫外光区类腐殖酸荧光峰消失,辅酶F420荧光峰强度有所降低.在长期接触实验后,甲烷杆菌属(Methanobacterium)所占比例从76.15%增至86.76%,而甲烷丝菌属(Methanothrix)所占比例从17.1%降至7.51%,Methanothrix对于Fe3O4NPs更为敏感;总细菌群落变化明显,其中变形菌门(Proteobacteria)所占比例从66.44%降至47.16%,放线菌门(Actinobacteria)所占比例从8.97%增至17.33%,拟杆菌门(Bacteroidetes)所占比例从8.07%增至17.74%,厚壁菌门和拟杆菌门比例的增加对有机物的厌氧水解过程发挥积极的作用.
In this study,the effects of magnetic Fe_3O_4 nanoparticles(Fe_3O_4 NPs) on soluble microbial products(SMP),loosely bound extracellular polymeric substances(LB-EPS),and tightly bound extracellular polymeric substances(TB-EPS) in anaerobic granular sludge were examined. In addition,the anaerobic granular sludge interior microbial community dynamics were investigated using high-throughput sequencing. The results demonstrated that the removal rate of COD was 83. 6% after long-term exposure in the experimental reactor,namely,the anaerobic reactor containing Fe_3O_4 NPs. It was reduced by 5. 7% in comparison with the removal rate in the control reactor. The total amount of TB-EPS in anaerobic granular sludge in the experimental and control reactors was178. 20 mg·g-1 and 138. 24 mg·g-1,respectively,while the total amount of SMP in anaerobic granular sludge was 34. 88 mg·L-1 and27. 44 mg·L-1,respectively. With regard to the LB-EPS in anaerobic granular sludge in the experimental reactor,the peak of humic acid disappeared and the peak intensity of coenzyme F420 decreased slightly using excitation-emission matrix(EEM) fluorescence spectra. In terms of the microbial community dynamics in the experimental reactor,the abundance of Methanobacterium was greatly augmented from 76. 15% to 86. 76%; whereas,the abundance of Methanothrix decreased from 17. 1% to 7. 51%. This indicated that Methanothrix was more sensitive to Fe_3O_4 NPs. Moreover,the changes in bacterial communities were evident:(1) the abundance of Proteobacteria dropped from 66. 44% to 47. 16%;(2) the abundance of Actinobacteria grew from 8. 97% to 17. 33%; and(3) the abundance of Bacteroidetes increased from 8. 07% to 17. 74%. The increasing abundance of Actinobacteria and Bacteroidetes plays a positive role in the anaerobic hydrolysis of organic matter.
引文
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