Department of Environmental Science and Engineering, University of Science & Technology of China, Hefei 230026, China.
USTC-CityU Joint Advanced Research Center, Suzhou Institute for Advance Resmuchearch of USTC, Suzhou, 215123, China.
Nanoscale. 2022 Jun 16;14(23):8409-8417. doi: 10.1039/d2nr01777f.
Inorganic-biological hybrid systems (bio-hybrids), comprising fermentative bacteria and inorganic semiconductor photosensitizers for synergistic utilization of solar energy and organic wastes, offer opportunities for sustainable fuel biosynthesis, but the low quantum efficiency, photosensitizer biotoxicity and inability for self-regeneration are remaining hurdles to practical application. Here, we unveil a previously neglected role of oxygen in suppressing the biosynthesis of cadmium selenide quantum dots (CdSe QDs) and the metabolic activities of , and accordingly propose a simple oxygen-regulation strategy to enable the self-assembly of bacterial-QD hybrids for efficient solar hydrogen production. Shifting from aerobic to anaerobic biosynthesis significantly lowered the intracellular reactive oxygen species level and increased NADPH and thiol-protein production, enabling a two-order-of-magnitude higher bio-QD synthesis rate and resulting in CdSe-rich products. Bacteria with abundant biocompatible intracellular bio-QDs naturally formed a highly active and self-regenerable bio-hybrid and achieved a quantum efficiency of 28.7% for hydrogen production under visible light, outperforming all the existing bio-hybrids. It also exhibited high stability during cyclic operation and robust performance for treating real wastewater under simulated sunlight. Our work provides valuable new insights into the metallic nanomaterial biosynthesis process to guide the design of self-assembled bio-hybrids towards sustainable energy and environmental applications.
无机-生物杂化系统（bio-hybrids）由发酵细菌和无机半导体光解剂组成，可协同利用太阳能和有机废物，为可持续燃料生物合成提供了机会，但量子效率低、光解剂生物毒性以及自我再生能力不足等问题仍然是实际应用的障碍。在这里，我们揭示了氧气在抑制硒化镉量子点（CdSe QDs）生物合成和代谢活性方面的一个以前被忽视的作用，因此提出了一种简单的氧气调控策略，使细菌-QD 杂化体能够进行有效的太阳能制氢。从需氧生物合成转变为厌氧生物合成可显著降低细胞内活性氧水平，并增加 NADPH 和硫醇蛋白的产生，从而使生物-QD 的合成速率提高两个数量级，并得到富含 CdSe 的产物。具有丰富生物相容性细胞内生物-QD 的细菌自然形成了高度活跃和可自我再生的生物杂化体，在可见光下制氢的量子效率达到 28.7%，优于所有现有的生物杂化体。它在循环操作过程中也表现出很高的稳定性，在模拟阳光下处理实际废水时具有稳健的性能。我们的工作为金属纳米材料生物合成过程提供了有价值的新见解，为自组装生物杂化体在可持续能源和环境应用方面的设计提供了指导。
