Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, China.
Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, China.
Water Res. 2022 Jan 1;208:117860. doi: 10.1016/j.watres.2021.117860. Epub 2021 Nov 11.
The present nitrogen fixation industry is usually energy-intensive and environmentally detrimental. Therefore, it is appealing to find alternatives. Here, we achieved both a synchronized biological nitrogen fixation and electric energy production by using Geobacter sulfurreducens in a microbial electrochemical system. The results showed that G. sulfurreducens was able to fix nitrogen depending on anode respiration, producing a maximum current density of 0.17 ± 0.015 mA cm and a nitrogen-fixing activity of ca. 0.78 μmol CH mg protein h, thereby achieving a net total nitrogen-fixing rate of ca. 5.6 mg L day. Specifically, nitrogen fixation did not impair coulombic efficiency. Transcriptomic and metabolic analyses demonstrated that anode respiration provided sufficient energy to drive nitrogen fixation, and in turn nitrogen fixation promoted anode respiration of the cell by increasing acetate catabolism but reducing acetate anabolism. Furthermore, we showed that G. sulfurreducens could be supplied in a bioelectrochemical system for N-deficient wastewater treatment to relieve N-deficiency stress contributing to the formation of an electroactive biofilm, thereby simultaneously achieving nitrogen fixation, current generation and dissoluble organic carbon removal. Our study revealed a synergistic effect between biological nitrogen fixation and current generation by G. sulfurreducens, providing a green nitrogen fixation alternative through shifting the nitrogen fixation field from energy consumption to energy production and having implications for N-deficient wastewater treatment.
目前的固氮工业通常是能源密集型和对环境有害的。因此，寻找替代品是很有吸引力的。在这里，我们通过在微生物电化学系统中使用脱硫弧菌（Geobacter sulfurreducens）实现了生物固氮和电能的同步生产。结果表明，脱硫弧菌能够依靠阳极呼吸固定氮，产生最大电流密度为 0.17 ± 0.015 mA cm 和大约 0.78 μmol CH mg 蛋白 h 的固氮活性，从而实现大约 5.6 mg L day 的净总固氮速率。具体来说，固氮不会损害库仑效率。转录组学和代谢分析表明，阳极呼吸为固氮提供了足够的能量，而固氮通过增加乙酸分解代谢但减少乙酸合成代谢来促进细胞的阳极呼吸。此外，我们表明，脱硫弧菌可以在生物电化学系统中为缺氮废水处理提供氮源，缓解氮缺乏应激，有助于形成电活性生物膜，从而同时实现固氮、电流生成和溶解有机碳去除。我们的研究揭示了脱硫弧菌生物固氮和电流生成之间的协同效应，通过将固氮领域从能源消耗转变为能源生产，为绿色固氮提供了一种替代方法，并对缺氮废水处理具有重要意义。
