School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou, China.
School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou, China; National and Local Joint Engineering Laboratory of Municipal Sewage Resource Utilization Technology, No. 1 Kerui Road, Suzhou, China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, No. 1 Kerui Road, Suzhou, China.
Bioresour Technol. 2020 Dec;318:124274. doi: 10.1016/j.biortech.2020.124274. Epub 2020 Oct 17.
This study investigated the activity of partial denitrification (PD) biomass/key enzymes, functional gene expressions in response to 0 ~ 50 mg/L hydroxylamine (NHOH) addition. Results indicated that NHOH contributed to nitrite (NO-N) production, facilitating the maximum increase of nitrate (NO-N) to NO-N transformation ratio to 80.47 ± 2.82%, leading to 2.56-fold NO-N higher than those of control. The observed transient inhibitory effect on NO-N reduction process was attributed by high-level NHOH (35 ~ 50 mg/L). Enzymatic assays revealed the enhanced activity of both NO-N and NO-N reductase while the former showed obvious superiority which led to high NO-N accumulation. These results were further confirmed by the corresponding functional genes (narG, napA, nirS and nirK). Besides, negative influence of NHOH addition was limited to PD aggregates, due to the increasing secretion of extracellular polymeric substances (EPS) as well as proteins/polysaccharides ratios in tightly-bound structure of EPS.
本研究考察了部分反硝化（PD）生物量/关键酶的活性以及功能基因表达对 050mg/L 羟胺（NHOH）添加的响应。结果表明，NHOH 促进了亚硝酸盐（NO-N）的产生，使得硝酸盐（NO-N）向 NO-N 转化率的最大增加达到 80.47±2.82%，导致 NO-N 比对照高 2.56 倍。观察到的对 NO-N 还原过程的瞬时抑制作用归因于高水平的 NHOH（3550mg/L）。酶活性测定显示，NO-N 和 NO-N 还原酶的活性均增强，而前者表现出明显的优势，导致 NO-N 的大量积累。这些结果通过相应的功能基因（narG、napA、nirS 和 nirK）进一步得到证实。此外，NHOH 添加的负面影响仅限于 PD 聚集体，这是由于细胞外聚合物物质（EPS）的分泌增加以及 EPS 紧密结合结构中蛋白质/多糖的比例增加所致。
