Engineering Cyanobacterium with Transmembrane Electron Transfer Ability for Bioelectrochemical Nitrogen Fixation
Engineering Cyanobacterium with Transmembrane Electron Transfer Ability for Bioelectrochemical Nitrogen Fixation
复制标题
DOI：
10.1021/acscatal.1c03038
复制
发表时间：
2021-10-15
期刊：
影响因子：
12.9
通讯作者：
Minteer, Shelley D.
中科院分区：
文献类型：
--
作者：
Dong, Fangyuan;Lee, Yoo Seok;Minteer, Shelley D.
生物电化学固氮作为一种在温和条件下实现氨合成的有前途的方法受到越来越多的关注。然而，目前开发的微生物e-BNF系统都依赖于可扩散介质来在细菌内递送氧化还原当量。使用可扩散介质的挑战包括毒性、低效的跨膜扩散、介质失活、介质污染和低能量效率。到目前为止，e-BNF通过跨膜电子摄取而不使用扩散电子介质尚未报道。在此，我们描述了一种遗传策略，工程蓝细菌细长聚球藻PCC 7942与跨膜电子转移（泰特）的能力，实现e-BNF不添加可溶性介质。工程化的S.利用细胞色素OmcS对具有N-2固定活性的细长体PCC 7942菌株Se-nif进行了进一步的转化，该细胞色素OmcS对Gephalosp的胞外电子转移（EET）能力有贡献。工程化的Senifom菌株表现出增强的泰特能力，导致其NH3产生速率比相应的Se-nif菌株高约13倍。Senifom e-BNF系统的法拉第效率计算为约23.3%，高于先前报道的e-BNF系统。对所获得的胞外电子的电子途径进行了简要分析，并提出了Senifom菌株的胞外电子摄取机制。这项工作表明，基因工程导管可以促进从电极到活细胞的跨膜电子通信，从而为生物电合成技术，特别是e-BNF系统和铵生产提供见解。
Increasing attention has been paid to bioelectrochemical nitrogen fixation (e-BNF) as a promising approach to achieve the NH3 synthesis under mild conditions. However, currently developed microbial e-BNF systems all rely on diffusible mediators to deliver redox equivalents inside the bacteria. Challenges of using diffusible mediators include toxicity, inefficient transmembrane diffusion, mediator inactivation, mediator contamination, and low energy efficiency. To date, e-BNF through transmembrane electron uptake without using diffusible electron mediators has not yet been reported. Herein, we describe a genetic strategy to engineer cyanobacterium Synechococcus elongatus PCC 7942 with transmembrane electron transfer (TET) ability to realize e-BNF without the addition of soluble mediators. The engineered S. elongatus PCC 7942 strain Se-nif with N-2 fixation activity was further transformed with an outer membrane protein cytochrome S OmcS, which contributes for the extracellular electron transfer (EET) ability of Geobacter sp. The engineered Senifom strain exhibited enhanced TET ability resulting in an approximately 13-fold higher NH3 production rate than the corresponding Se-nif strain. The Faradaic efficiency of the Senifom e-BNF system was calculated to be approximately 23.3%, which is higher than the previously reported e-BNF systems. The electron pathway of the obtained extracellular electron was briefly analyzed and an extracellular electron uptake mechanism in the Senifom strain was proposed. This work demonstrates that a genetically engineered conduit can facilitate transmembrane electronic communication from the electrode to living cells, thereby providing insights into bioelectrosynthesis technology, especially the e-BNF systems and ammonium production.