Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
California NanoSystems Institute (CNSI), University of California, Los Angeles, Los Angeles, CA, 90095, USA.
Nat Commun. 2020 Mar 20;11(1):1505. doi: 10.1038/s41467-020-15314-9.
Root nodules are agricultural-important symbiotic plant-microbe composites in which microorganisms receive energy from plants and reduce dinitrogen (N) into fertilizers. Mimicking root nodules using artificial devices can enable renewable energy-driven fertilizer production. This task is challenging due to the necessity of a microscopic dioxygen (O) concentration gradient, which reconciles anaerobic N fixation with O-rich atmosphere. Here we report our designed electricity-powered biological|inorganic hybrid system that possesses the function of root nodules. We construct silicon-based microwire array electrodes and replicate the O gradient of root nodules in the array. The wire array compatibly accommodates N-fixing symbiotic bacteria, which receive energy and reducing equivalents from inorganic catalysts on microwires, and fix N in the air into biomass and free ammonia. A N reduction rate up to 6.5 mg N per gram dry biomass per hour is observed in the device, about two orders of magnitude higher than the natural counterparts.
根瘤是农业中重要的共生植物-微生物复合物，其中微生物从植物中获取能量，并将氮气（N）还原为肥料。使用人工装置模拟根瘤可以实现可再生能源驱动的肥料生产。由于需要微观的氧气（O）浓度梯度来协调厌氧固氮与富含 O 的大气，因此这项任务具有挑战性。在这里，我们报告了我们设计的电能驱动的生物|无机混合系统，该系统具有根瘤的功能。我们构建了基于硅的微丝阵列电极，并在阵列中复制了根瘤的 O 梯度。该丝阵列兼容固氮共生细菌，这些细菌从微丝上的无机催化剂中获取能量和还原当量，并将空气中的氮固定到生物质和游离氨中。在该装置中观察到高达每克干生物质每小时 6.5 毫克 N 的还原速率，比天然对应物高出两个数量级。
