五氯苯酚对污泥性能和功能基因表达水平的影响

氯酚废水是一类广泛存在于环境的典型工业废水，具有显著的生态毒性，为探讨废水中氯酚类化合物对污泥性能和功能基因表达水平的影响，采用HRT（水力停留时间）为8 h、SBR（间歇曝气的序批式生物反应器）处理进水浓度为2 mg/L的PCP（五氯苯酚）废水，并与处理不含PCP的废水作对比分析，探讨PCP对污染物去除和微生物菌群的影响，并分析PCP诱导下污泥中Pseudomonas功能基因的表达水平.结果表明:①1~90 d，进水浓度为2 mg/L的PCP严重抑制污泥活性，出水ρ（COD_Cr）超过100 mg/L，PCP降解去除缓慢，而对照组出水ρ（COD_Cr）在31.6 mg/L左右波动.90 d后，降解PCP的优势菌群富集，水相、泥相PCP被降解去除，但PCP的毒性作用使其出水ρ（COD_Cr）仍高于对照组.②经PCP长期驯化污泥富集的优势菌属为Chondromyces、Ignavibacterium、Thauera、Pseudoxanthomonas、Bosea、Achromobacter、Comamonas和Salimesophilobacter，均归属于变形菌门和厚壁菌门，在降解氯酚类污染物方面起着重要作用.③当处理PCP的SBR处于稳定运行阶段时，SBR运行周期末污泥中降解PCP的菌属Pseudomonas调控ATP水解酶（ATPase）、过氧化氢酶（CAT）和细胞色素p450（CYP450）的功能基因表达被激活，而调控超氧化物歧化酶（SODb）、氨单加氧酶（AM）、脱氯水解酶（HDLH）和甘油三磷酸脱氢酶（GAPDH）的功能基因表达被抑制，即活性污泥中微生物调控不同基因的表达受进水PCP的抑制或激活.研究显示:进水PCP诱导SBR富集的优势菌属可实现废水中PCP的去除，起到削减废水毒性的作用；通过分析不同优势菌属的相关功能基因表达，可加强对不同微生物降解污染物机理的认识. 

Effects of Pentachlorophenol on Sludge Performance and Functional Genes Expression Level in Sequencing Batch Bioreactors

Chlorophenol wastewater widely exists in the environment, and it is a typical industrial wastewater with significant biotoxicity. To explore the effects of chlorophenols in wastewater on sludge performance and functional gene expression levels, a sequencing batch bioreactor (SBR) was controlled at 8 h hydraulic retention time (HRT) and intermittent aeration modes to treat 2 mg/L pentachlorophenol (PCP) influent, and was compared with the control SBR without PCP. The results showed that: (1) In the first 90 days of treatment, the sludge activity was significantly inhibited by the influent PCP at the concentration of 2 mg/L, the effluent COD_Cr exceeded 100 mg/L and the biodegradation of PCP was slow. However, the effluent COD_Cr in the control SBR fluctuated within the range of 31.6 mg/L. After 90 days, the main microbes for PCP biodegradation were enriched, and the PCP in the water and sludge phases was biodegraded. The effluent COD_Cr in the acclimated SBR was still higher than the control SBR due to the toxicity of PCP. (2) After the activated sludge was long-term acclimated by PCP, the dominant microbes for PCP biodegradation belonged to Proteobacteria and Firmicutes were enriched, including Chondromyces, Ignavibacterium, Thauera, Pseudoxanthomonas, Bosea, Achromobacter, Comamonas and Salimesophilobacter, which had important roles in degrading chlorophenol pollutants. (3) When the acclimated SBR with influent PCP operated at the stable stages, the expression of functional genes for regulating ATPase, catalase (CAT) and cytochrome p450 (CYP450) was activated for the genus of Pseudomonas in sludge at the end of SBR cycle, while the expression of functional genes for regulating superoxide dismutase (SODb), ammonia monooxygenase (AM), haloacid dehalogenase-like hydrolase (HDLH) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) was suppressed, i.e. the gene expression for microbial regulation in activated sludge might be suppressed or activated by the influent PCP. The research showed that the influent PCP induced the enrichment of dominant microbes in SBR, achieving the PCP removal and then reducing the toxicity of wastewater. The understanding of biodegradation mechanism of pollutants can be improved by analyzing the expression of related functional genes from different dominant microbes.