National and Local Joint Engineering Laboratory for Municipal Sewage Resource Utilization Technology, Suzhou University of Science and Technology, Suzhou 215002, China; School of Environment Science and Engineering, Suzhou University of Science and Technology, Suzhou 215002, China.
School of Environment Science and Engineering, Suzhou University of Science and Technology, Suzhou 215002, China.
Sci Total Environ. 2019 Nov 20;692:582-588. doi: 10.1016/j.scitotenv.2019.07.078. Epub 2019 Jul 6.
Anammox bacteria are chemolithotrophic organisms growing on the conversion of ammonium and nitrite with bicarbonate as the sole carbon source. Meanwhile, anammox bacteria display a metabolic versatility to sustain their metabolism. However, there is less attention on the Fe/Fe-dependent autotrophic denitrification by anammox consortia. In this study, the autotrophic nitrate reduction using different valence of iron (Fe, Fe and Fe+ Fe, respectively) as electron donors by anammox consortia were firstly explored in continuous feeding mode. Results revealed anammox consortia showed high adaptability to the niche wherein containing nitrate and iron. They could generate nitrite and ammonium from iron-dependent nitrate reduction, and hence support their central metabolism. During 60-days operation, the maximum nitrate and total nitrogen removal efficiency reached 88.43% and 80.77%, respectively, with coexistence of Fe and Fe. The expression of key functional genes involved in nitrate reduction (including narG, napA and nrfA) in 16S rRNA level revealed the coupling of dissimilatory nitrate reduction to nitrite, dissimilatory nitrite reduction to ammonia (DNRA), and anammox processes possibly play pivotal role in nitrogen loss under Fe/Fe condition. Meanwhile, abiotic reduction by Fe/Fe also contributed nitrate reduction to provide nitrite and ammonium for anammox consortia. Activities of two vital enzymes hydrazine dehydrogenase (HDH) and nitrate oxidoreduetase (NAR) also inferred higher microbial activities with co-existence of Fe and Fe. The present study confirms and further extends the versatile metabolisms of Anammox consortia, also it can help to circumvent the accumulation of nitrate produced by anammox process itself and increase the quality of discharge.
厌氧氨氧化菌是化能自养微生物，以碳酸氢盐为唯一碳源，通过将氨氮和亚硝氮转化来生长。同时，厌氧氨氧化菌表现出代谢的多功能性，以维持其新陈代谢。然而，对于厌氧氨氧化菌协同作用下的 Fe/Fe 依赖性自养反硝化作用的关注较少。在本研究中，首次在连续进料模式下探索了不同价态的铁（Fe、Fe 和 Fe+Fe）作为电子供体时，厌氧氨氧化菌协同作用对自养硝酸盐还原的影响。结果表明，厌氧氨氧化菌对含有硝酸盐和铁的生态位具有很强的适应性。它们可以从铁依赖性硝酸盐还原中产生亚硝酸盐和铵，从而支持其中心代谢。在 60 天的运行过程中，当共存 Fe 和 Fe 时，最大硝酸盐和总氮去除效率分别达到 88.43%和 80.77%。16S rRNA 水平上参与硝酸盐还原的关键功能基因（包括 narG、napA 和 nrfA）的表达表明，异化硝酸盐还原为亚硝酸盐、异化亚硝酸盐还原为氨（DNRA）以及厌氧氨氧化过程可能在 Fe/Fe 条件下对氮损失起关键作用。同时，Fe/Fe 的非生物还原也有助于硝酸盐还原，为厌氧氨氧化菌提供亚硝酸盐和铵。肼脱氢酶（HDH）和硝酸盐氧化还原酶（NAR）两种重要酶的活性也推断出共存 Fe 和 Fe 时微生物活性更高。本研究证实并进一步扩展了厌氧氨氧化菌的多功能代谢，同时也有助于避免由厌氧氨氧化过程本身产生的硝酸盐的积累，提高排放水的质量。
