Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Centre of Chemical Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, PR China.
State Key Laboratory of Marine Resource Utilization in South China Sea, College of Information Science & Technology, Hainan University, Haikou, 570228, PR China.
Nat Commun. 2018 Sep 7;9(1):3637. doi: 10.1038/s41467-018-05995-8.
The slow rate of extracellular electron transfer (EET) of electroactive microorganisms remains a primary bottleneck that restricts the practical applications of bioelectrochemical systems. Intracellular NAD(H/) (i.e., the total level of NADH and NAD) is a crucial source of the intracellular electron pool from which intracellular electrons are transferred to extracellular electron acceptors via EET pathways. However, how the total level of intracellular NAD(H/) impacts the EET rate in Shewanella oneidensis has not been established. Here, we use a modular synthetic biology strategy to redirect metabolic flux towards NAD biosynthesis via three modules: de novo, salvage, and universal biosynthesis modules in S. oneidensis MR-1. The results demonstrate that an increase in intracellular NAD(H/) results in the transfer of more electrons from the increased oxidation of the electron donor to the EET pathways of S. oneidensis, thereby enhancing intracellular electron flux and the EET rate.
电活性微生物的胞外电子传递 (EET) 缓慢仍然是限制生物电化学系统实际应用的主要瓶颈。细胞内 NAD(H/)（即 NADH 和 NAD 的总量）是细胞内电子库的重要来源，细胞内电子通过 EET 途径从细胞内电子库转移到细胞外电子受体。然而，细胞内 NAD(H/) 的总量如何影响希瓦氏菌属中的 EET 速率尚不清楚。在这里，我们使用模块化合成生物学策略通过三个模块将代谢通量重新定向到 NAD 生物合成：从头合成、补救和通用生物合成模块在 S. oneidensis MR-1 中。结果表明，细胞内 NAD(H/) 的增加导致更多电子从电子供体的增加氧化转移到 S. oneidensis 的 EET 途径，从而增强了细胞内电子流和 EET 速率。
