Photoelectrotrophic denitrification (PEDeN) using bio-hybrids has the potential to remove nitrate (NO₃⁻) from wastewater in an economical and sustainable way. As a gas of global concern, the mechanisms of nitrous oxide (N₂O) emissions during this novel process remain unclear. Herein, a self-photosensitized bio-hybrid, i. e., Thiobacillus denitrificans-cadmium sulfide, was constructed and the factors affecting N₂O emissions during PEDeN by the bio-hybrids were investigated. The system was sensitive to the input NO₃⁻-N and NO₂⁻-N, resulting in changes in the N₂O/(N₂+N₂O) ratio from 1% to 95%. In addition to free nitrous acid (FNA), reactive oxidative species (ROS) were a unique factor affecting N₂O emission during PEDeN. Importantly, the N₂O reduction step exhibited greater susceptibility to the ROS than nitrate reduction step. The contributions of hydrogen peroxide (H₂O₂), superoxides (O₂^−•), hydroxyl radicals (•OH) and FNA to the inhibition of N₂O reduction were >15.0%, >5.4%, 1.3%, and <70.2%, respectively for a reduction of 13.5 mg/L NO₃⁻-N. A significant down-regulation of the relative transcription of the gene nosZ demonstrated that the inhibition of N₂O reductase occurred at the gene level. This finding has important implications not only for mitigating N₂O emissions during the PEDeN process but also for encouraging a reexamination process of N₂O emissions in nature, particularly in systems in which ROS are present during the denitrification process.

Photoelectrotrophic脱氮（佩登）采用生物杂种具有以除去硝酸盐的电位（NO ₃ ^-从废水以经济的和可持续的方式）。作为一种全球关注的气体，这种新颖过程中一氧化二氮（N ₂ O）排放的机制仍不清楚。在此，构建了一种自光敏生物杂交体，即反硝化硫杆菌-硫化镉，并研究了生物杂交体在PEDeN中影响N ₂ O排放的因素。系统对输入的NO ₃ ^-- N和NO ₂ ^-- N敏感，导致N ₂ O /（N ₂ + N ₂O）比率从1％到95％。除游离亚硝酸（FNA）外，反应性氧化物质（ROS）是影响PEDeN期间N ₂ O排放的独特因素。重要的是，与硝酸盐还原步骤相比，N ₂ O还原步骤对ROS的敏感性更高。过氧化氢（H ₂ O ₂），超氧化物（O _2- ^•），羟基自由基（•OH）和FNA对抑制N ₂ O还原的贡献分别为> 15.0％，> 5.4％，1.3％和<减少13.5 mg / L NO ₃ ^-- N分别为70.2％。nosZ基因相对转录的显着下调表明N的抑制₂ O还原酶发生在基因水平。这一发现不仅对减少PEDeN过程中的N ₂ O排放有重要意义，而且对于鼓励自然界中特别是在反硝化过程中存在ROS的系统中N ₂ O排放的重新检查过程也具有重要意义。