College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China.
College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China.
Chemosphere. 2022 Nov;307(Pt 4):136078. doi: 10.1016/j.chemosphere.2022.136078. Epub 2022 Aug 16.
Identification of dissimilatory nitrate reduction to ammonium (DNRA) and denitrification in the dynamic cake layer of a full-scale anoixc dynamic membrane bioreactor (AnDMBR) for treating hotel laundry wastewater was studied. A series of experiments were conducted to understand the contributions of DNRA and canonical denitrification activities in the dynamic cake layer of the AnDMBR. The dynamic cake layer developed included two phases - a steady transmembrane pressure (TMP) increase at 0.24 kPa/day followed by a sharp TMP jump at 1.26 kPa/day four to five days after the AnDMBR start-up. The nitrogen mass balance results showed that canonical denitrification was predominant during the development of the dynamic cake layer. However, DNRA activity and accumulation of bacteria equipped with a complete DNRA pathway showed a positive correlation to the development of the dynamic cake layer. Our metagenomic analysis identified an approximately 18% of the dynamic cake layer bacterial community has a complete DNRA pathway. Pannonibacter (1%), Thauera (0.8%) and Pseudomonas (3%) contained all genes encoding for funcional enzymes of both DNRA (nitrate reductase and DNRA nitrite reductase) and denitrification (nitrate reductase, nitrous oxide reductase and nitric oxide reductase). No other metagenome-assembled genomes (MAGs) possessed a complete cononical denitrification pathway, indicating food-chain-like interactions of denitrifiers in the dynamic cake layer. We found that COD loading rate could be used to control DNRA and canonical denitrification activities during the dynamic cake layer formation.
采用全程动态膜生物反应器（AnDMBR）处理宾馆洗衣废水过程中，对动态膜层中异化硝酸盐还原为铵（DNRA）和反硝化作用进行了鉴定。进行了一系列实验以了解 DNRA 和经典反硝化作用在 AnDMBR 动态膜层中的贡献。所形成的动态膜层包括两个阶段 - 在 AnDMBR 启动后四到五天，每天以 0.24 kPa 的恒定跨膜压力（TMP）增加，然后以 1.26 kPa 的快速 TMP 增加。氮质量平衡结果表明，在动态膜层的发展过程中，经典反硝化作用占主导地位。然而，DNRA 活性和配备完整 DNRA 途径的细菌的积累与动态膜层的发展呈正相关。我们的宏基因组分析确定，大约 18％的动态膜层细菌群落具有完整的 DNRA 途径。Pannonibacter（1％），Thauera（0.8％）和Pseudomonas（3％）均包含编码功能性酶的所有基因，这些酶既具有 DNRA（硝酸盐还原酶和 DNRA 亚硝酸盐还原酶）又具有反硝化作用（硝酸盐还原酶，亚硝酸盐还原酶和一氧化氮还原酶）。没有其他宏基因组组装基因组（MAG）具有完整的经典反硝化途径，这表明在动态膜层中，反硝化菌之间存在食物链样相互作用。我们发现，COD 加载速率可用于控制动态膜层形成过程中的 DNRA 和经典反硝化作用。
