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.
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.
J Hazard Mater. 2024 Jun 5;471:134329. doi: 10.1016/j.jhazmat.2024.134329. Epub 2024 Apr 17.
Due to the refractory of 1 H-1,2,4-triazole (TZ), conventional anaerobic biological treatment technology is usually restricted by low removal efficiency and poor system stability. In this study, TZ biodegradation and nitrate reduction was coupled to improve the removal efficiency of TZ from polluted wastewater. Batch assay was performed with pure culture strain Raoultella sp. NJUST42, which was reported to have the capability to degrade TZ in our previous study. Based on batch assay result, complete removal of TZ could be achieved in the presence of nitrate, whereas only 50% of TZ could be removed in the control system. Long-term stability experiment indicated that the relative abundance of microorganisms (Bacteroidetes_vadinHA17, Georgenia, Anaerolinea, etc) was obviously enhanced under nitrate reduction condition. During long-term period, major intermediates for TZ biodegradation such as [1,2,4]Triazolidine-3,5-diol, hydrazine dibasic carboxylic acid and carbamic acid were detected. A novel TZ biotransformation approach via hydration, TZ-ring cleavage, deamination and oxidation was speculated. PICRUSt1 and KEGG pathway analyses indicated that hydration (dch), oxidation (adhD, oah, pucG, fdhA) of TZ and nitrate reduction (Nar, napA, nrfA, nirBK, norB, nosZ) were significantly enhanced in the presence of nitrate. Moreover, the significant enrichment of TCA cycle (gab, sdh, fum, etc.) indicated that carbon and energy metabolism were facilitated with the addition of nitrate, thus improved TZ catabolism. The proposed mechanism demonstrated that TZ biodegradation coupled with nitrate reduction would be a promising approach for efficient treatment of wastewater contaminated by TZ.
由于 1H-1,2,4-三唑（TZ）的抗药性，传统的厌氧生物处理技术通常受到去除效率低和系统稳定性差的限制。在本研究中，通过耦合 TZ 生物降解和硝酸盐还原来提高受污染废水中 TZ 的去除效率。批处理试验是用纯培养菌株 Raoultella sp. NJUST42 进行的，该菌株在我们之前的研究中被报道具有降解 TZ 的能力。根据批处理试验结果，在存在硝酸盐的情况下可以完全去除 TZ，而在对照系统中只能去除 50%的 TZ。长期稳定性试验表明，在硝酸盐还原条件下，微生物（拟杆菌门_vadinHA17、乔治亚菌属、产线菌属等）的相对丰度明显增强。在长期过程中，检测到 TZ 生物降解的主要中间产物，如[1,2,4]三唑烷-3,5-二醇、肼二羧酸和氨基甲酸。推测了一种通过水合、TZ 环裂解、脱氨和氧化进行 TZ 生物转化的新方法。PICRUSt1 和 KEGG 途径分析表明，在硝酸盐存在的情况下，TZ 的水合（dch）、氧化（adhD、oah、pucG、fdhA）和硝酸盐还原（Nar、napA、nrfA、nirBK、norB、nosZ）显著增强。此外，TCA 循环（gab、sdh、fum 等）的显著富集表明，加入硝酸盐后促进了碳和能量代谢，从而提高了 TZ 代谢。提出的机制表明，将 TZ 生物降解与硝酸盐还原相结合将是处理 TZ 污染废水的一种很有前途的方法。
