Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100000, China; College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China.
Civil and Environmental Engineering, University of California, Los Angeles, CA 90095, USA.
J Hazard Mater. 2021 Jun 15;412:125157. doi: 10.1016/j.jhazmat.2021.125157. Epub 2021 Jan 23.
This study used integrated omics technologies to investigate the potential novel pathways and enzymes for 1,4-dioxane degradation by a consortium enriched from activated sludge of a domestic wastewater treatment plant. An unclassified genus belonging to Xanthobacteraceae increased significantly after magnetic nanoparticle-mediated isolation for 1,4-dioxane degraders. Species with relatively higher abundance (> 0.3%) were identified to present high metabolic activities in the biodegradation process through shotgun sequencing. The functional gene investigations revealed that Xanthobacter sp. 91, Xanthobacter sp. 126, and a Rhizobiales strain carried novel 1,4-dioxane-hydroxylating monooxygenase genes. Xanthobacter sp. 126 contained the genes coding for glycolate oxidase, which was the main enzyme responsible for utilization of 1,4-dioxane intermediates through the TCA cycle, and further proven by the specific glycolate oxidase inhibitor, α-hydroxy-2-pyridinemethanesulfonic acid. An expanded and detailed degradation pathway of 1,4-dioxane was proposed on the basis of the three major intermediates (2-hydroxy-1,4-dioxane, ethylene glycol, and oxalic acid) confirmed by metabolomics. These findings of microbial community and function as well as the novel pathway will be valuable in predicting natural attenuation or reconstruction of a bacterial consortium for enhanced remediation of 1,4-dioxane-contaminated sites as well as wastewater treatment.
本研究采用整合组学技术，从生活污水处理厂的活性污泥中富集的联合体中，研究了 1,4-二恶烷降解的潜在新途径和酶。在通过磁纳米颗粒介导分离 1,4-二恶烷降解菌后，一个未分类的属于黄杆菌科的属显著增加。通过鸟枪法测序，确定相对丰度较高（>0.3%）的物种在生物降解过程中具有较高的代谢活性。功能基因研究表明，黄杆菌属 91 号、黄杆菌属 126 号和根瘤菌属菌株携带新型 1,4-二恶烷羟化单加氧酶基因。黄杆菌属 126 号含有编码甘氨酸氧化酶的基因，该酶是通过 TCA 循环利用 1,4-二恶烷中间产物的主要酶，并且通过甘氨酸氧化酶的特异性抑制剂α-羟基-2-吡啶甲磺酸进一步证实。基于代谢组学确定的三种主要中间产物（2-羟基-1,4-二恶烷、乙二醇和草酸），提出了 1,4-二恶烷的扩展和详细降解途径。这些微生物群落和功能以及新途径的发现，对于预测自然衰减或细菌联合体的重建以增强 1,4-二恶烷污染场地的修复以及废水处理具有重要价值。
