Departments of Chemistry and Chemical & Biomolecular Engineering, Institute for Functional Intelligent Materials (I-FIM), National University of Singapore, Singapore, 119077, Singapore.
Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 639798, Singapore.
Adv Mater. 2022 Sep;34(37):e2203480. doi: 10.1002/adma.202203480. Epub 2022 Aug 3.
Microbial electrosynthesis-using renewable electricity to stimulate microbial metabolism-holds the promise of sustainable chemical production. A key limitation hindering performance is slow electron-transfer rates at biotic-abiotic interfaces. Here a new n-type conjugated polyelectrolyte is rationally designed and synthesized and its use is demonstrated as a soft conductive material to encapsulate electroactive bacteria Shewanella oneidensis MR-1. The self-assembled 3D living biocomposite amplifies current uptake from the electrode ≈674-fold over controls with the same initial number of cells, thereby enabling continuous synthesis of succinate from fumarate. Such functionality is a result of the increased number of bacterial cells having intimate electronic communication with the electrode and a higher current uptake per cell. This is underpinned by the molecular design of the polymer to have an n-dopable conjugated backbone for facile reduction by the electrode and zwitterionic side chains for compatibility with aqueous media. Moreover, direct arylation polycondensation is employed instead of the traditional Stille polymerization to avoid non-biocompatible tin by-products. By demonstrating synergy between living cells with n-type organic semiconductor materials, these results provide new strategies for improving the performance of bioelectrosynthesis technologies.
微生物电化学合成——利用可再生电能来刺激微生物代谢——有望实现可持续的化学生产。一个关键的限制因素是生物-非生物界面上缓慢的电子转移速率。在这里，我们合理设计并合成了一种新型 n 型共轭聚合物，并将其用作一种软导电材料来封装电活性细菌 Shewanella oneidensis MR-1。自组装的 3D 活生物复合材料使电流吸收比具有相同初始细胞数的对照物增加了约 674 倍，从而能够连续地从延胡索酸合成琥珀酸。这种功能是由于具有与电极进行电子通信的细菌细胞数量增加，以及每个细胞的电流吸收增加所致。这是通过聚合物的分子设计来实现的，聚合物具有 n 型可掺杂共轭主链，可通过电极轻易还原，以及两性离子侧链，与水性介质兼容。此外，采用直接芳基聚合而不是传统的 Stille 聚合来避免非生物相容性的锡副产物。通过展示活细胞与 n 型有机半导体材料之间的协同作用，这些结果为改善生物电化学合成技术的性能提供了新的策略。
