Wang Jing, Chi Qiang, Pan Ling, Zhang Ranran, Mu Yang, Shen Jinyou
Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Industry and Information Technology, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China.
Water Res. 2023 Aug 15;242:120200. doi: 10.1016/j.watres.2023.120200. Epub 2023 Jun 8.
Due to the recalcitrant nature of halogenated phenol, conventional anaerobic bioprocess is often limited by low removal efficiency and poor process stability. At the presence of electron acceptors such as nitrate, 4-bromophenol (4-BP) removal efficiency is significantly higher than that in the anaerobic control system, but the mechanism involved is still unclear. Therefore, an up-flow nitrate-reducing bioreactor (NRBR) was designed and consecutively performed for 215 days to explore the synergistic mechanism for BPs biodegradation and nitrate reduction. Complete 4-BP biodegradation could be obtained in NRBR at HRT and 4-BP loading rate of 24 h and 0.29 mol m d , while the TOC removal and nitrate reduction efficiencies were as high as 91.33±2.11% and 98.31±1.33%, respectively. Population evolution analyses revealed that the microorganisms involved in 4-BP debromination and biodegradation (Candidatus Peregrinibacteria, Denitratisoma, Anaerolineaceae and Ignavibacterium) as well as nitrate reduction (Denitratisoma, Anaerolineaceae, Limnobacter and Ignavibacterium) were significantly enriched in NRBR. Major intermediates during 4-BP biodegradation, including 4-bromocatechol, 4‑bromo-6-oxo-hexanoic acid and succinic acid were identified, while a distinct 4-BP biodegradation pathway via hydration, aromatic-ring cleavage, hydrolysis debromination and oxidation was expounded. Metagenomic analysis indicated that oxidation (had, pht4, boh, butA), hydrolysis debromination ((S)-2-haloacid dehalogenase) and bio-mineralization (gabD, sdhA) of 4-BP were largely enhanced in NRBR. Moreover, carbon, nitrogen, energy and amino acid metabolisms were significantly facilitated with the injection of nitrate in order to provide energy and electron, thus enhanced microbial activities and enzymatic reactions in NRBR. The proposed mechanism provides new insights into our mechanistic understanding of halogenated phenol biodegradation and the development of sustainable bioremediation strategies.
由于卤代酚的顽固性，传统厌氧生物处理过程往往受到去除效率低和工艺稳定性差的限制。在存在硝酸盐等电子受体的情况下，4-溴苯酚（4-BP）的去除效率显著高于厌氧控制系统，但其中涉及的机制仍不清楚。因此，设计了一个上流式硝酸盐还原生物反应器（NRBR），并连续运行215天，以探索BP生物降解和硝酸盐还原的协同机制。在水力停留时间（HRT）为24小时、4-BP负荷率为0.29 mol m⁻³ d⁻¹的条件下，NRBR中可实现4-BP的完全生物降解，而总有机碳（TOC）去除率和硝酸盐还原效率分别高达91.33±2.11%和98.31±1.33%。种群进化分析表明，参与4-BP脱溴和生物降解的微生物（候选 Peregrinibacteria、脱氮梭菌属、厌氧绳菌科和 Ignavibacterium）以及硝酸盐还原的微生物（脱氮梭菌属、厌氧绳菌科、Limnobacter 和 Ignavibacterium）在NRBR中显著富集。确定了4-BP生物降解过程中的主要中间产物，包括4-溴儿茶酚、4-溴-6-氧代己酸和琥珀酸，同时阐述了一条通过水合作用、芳环裂解、水解脱溴和氧化作用的独特4-BP生物降解途径。宏基因组分析表明，NRBR中4-BP的氧化（had、pht4、boh、butA）、水解脱溴（(S)-2-卤代酸脱卤酶）和生物矿化（gabD、sdhA）作用大大增强。此外，注入硝酸盐显著促进了碳、氮、能量和氨基酸代谢，以提供能量和电子，从而增强了NRBR中的微生物活性和酶促反应。所提出的机制为我们对卤代酚生物降解的机理理解以及可持续生物修复策略的开发提供了新的见解。
