Department of Environmental Science, Chongqing University, 174 Shapingba Road, Chongqing, 400044, China.
State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, 174 Shapingba Road, Chongqing, 400044, China; Department of Environmental Science, Chongqing University, 174 Shapingba Road, Chongqing, 400044, China.
Chemosphere. 2020 May;247:125968. doi: 10.1016/j.chemosphere.2020.125968. Epub 2020 Jan 21.
It was revealed that Anammox process promotes the anaerobic degradation of benzene under denitrification. This study investigates the effect of dissimilatory nitrate reduction to ammonium (DNRA) and exogenous ammonium on anaerobic ammonium oxidation bacteria (AnAOB) during the anaerobic degradation of benzene under denitrification. The results indicate that anammox occurs synergistically with organisms using the DNRA pathway, such as Draconibacterium and Ignavibacterium. Phylogenetic analysis showed 64% (16/25) and 36% (5/25) hzsB gene sequences, a specific biomarker of AnAOB, belonged to Candidatus 'Brocadia fuldiga' and Candidatus 'Kuenenia', respectively. Exogenous ammonium addition enhanced the anammox process and accelerated benzene degradation at a 1.89-fold higher average rate compared to that in the absence of exogenous ammonium and AnAOB belonged to Ca. 'Kuenenia' (84%) and Ca. 'Brocadia fuldiga' (16%). These results indicate that Ca. 'Brocadia fuldiga' could also play a role in DNRA. However, the diversity of abcA and bamA, the key anaerobic benzene metabolism biomarkers, remained unchanged. These findings suggest that anammox occurrence may be coupled with DNRA or exogenous ammonium and that anammox promotes anaerobic benzene degradation under denitrifying conditions. The results of this study contribute to understanding the co-occurrence of DNRA and Anammox and help explore their involvement in degradation of benzene, which will be crucial for directing remediation strategies of benzene-contaminated anoxic environment.
研究揭示了厌氧氨氧化过程可促进反硝化条件下苯的厌氧降解。本研究考察了异化硝酸盐还原为铵（DNRA）和外加铵对反硝化条件下苯厌氧降解过程中厌氧氨氧化菌（AnAOB）的影响。结果表明，厌氧氨氧化与 Draconibacterium 和 Ignavibacterium 等利用 DNRA 途径的微生物协同作用。系统发育分析显示，25 个 hzsB 基因序列中有 64%（16/25）和 36%（5/25）分别属于厌氧氨氧化菌的特定生物标志物“Candidatus 'Brocadia fuldiga'”和“Candidatus 'Kuenenia'”。外加铵的添加增强了厌氧氨氧化过程，并使苯的降解速率比无外加铵和无 AnAOB 时提高了 1.89 倍，此时 AnAOB 属于 Ca. 'Kuenenia'（84%）和 Ca. 'Brocadia fuldiga'（16%）。这些结果表明，Ca. 'Brocadia fuldiga' 也可能在 DNRA 中发挥作用。然而，abcA 和 bamA 的多样性，即厌氧苯代谢的关键生物标志物，保持不变。这些发现表明，厌氧氨氧化的发生可能与 DNRA 或外加铵有关，并且厌氧氨氧化可促进反硝化条件下苯的厌氧降解。本研究的结果有助于理解 DNRA 和厌氧氨氧化的共现，并有助于探索它们在苯降解中的作用，这对于指导受污染缺氧环境中苯的修复策略至关重要。
