Phenazines as model low-midpoint potential electron shuttles for photosynthetic bioelectrochemical systems.
Phenazines as model low-midpoint potential electron shuttles for photosynthetic bioelectrochemical systems.
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作为光合生物电气化学系统的模型低中点电子班车的模型。
DOI：
10.1039/d0sc05655c
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发表时间：
2021-01-15
期刊：
影响因子：
8.4
通讯作者：
Zhang JZ
中科院分区：
文献类型：
--
作者：
Clifford ER;Bradley RW;Wey LT;Lawrence JM;Chen X;Howe CJ;Zhang JZ
用于能量转换的生物电化学方法依赖于天然电子传输链到电极的有效布线。然而，最先进的外源性电子介体引起显著的能量损失，并且在生命系统的情况下，引起长期的细胞毒性。在这里，我们探索了新的选择标准外源电子调解检查吩嗪作为新的低中点电位分子布线的光合电子传递链的蓝藻集胞藻属PCC 6803电极。我们确定绿脓菌素（PYO）作为一种有效的细胞可渗透的吩嗪，可以收获电子高度还原点的光合作用。观察到PYO介导的光电流比无介体系统高4倍，与常见的高中点电位介体2，6-二氯-1，4-苯醌（DCBQ）相比，能量增益为200 mV。PYO的低中点电位导致O2还原副反应，其与光电流产生显著竞争;调节介质浓度对于在避免急性细胞毒性的同时战胜副反应是重要的。DCBQ介导的光电流通常要高得多，但也迅速衰减，并且在添加新鲜介质的情况下不可恢复。这表明细胞可以随着时间的推移获得DCBQ抗性。相比之下，PYO引起了更大的电流增强，尽管共同产生不需要的活性氧，和PYO暴露的细胞没有发展获得性电阻。此外，我们证明了蓝藻可以通过基因工程来内源性地产生PYO，以改善长期前景。总的来说，这项研究建立了能量增益可以通过使用低电位吩嗪在光合生物电化学系统中实现，并量化的因素和权衡，确定有效的调解在生活生物电化学系统。吩嗪被探索为新型的低中点电位分子，用于将蓝藻连接到电极上。
Bioelectrochemical approaches for energy conversion rely on efficient wiring of natural electron transport chains to electrodes. However, state-of-the-art exogenous electron mediators give rise to significant energy losses and, in the case of living systems, long-term cytotoxicity. Here, we explored new selection criteria for exogenous electron mediation by examining phenazines as novel low-midpoint potential molecules for wiring the photosynthetic electron transport chain of the cyanobacterium Synechocystis sp. PCC 6803 to electrodes. We identified pyocyanin (PYO) as an effective cell-permeable phenazine that can harvest electrons from highly reducing points of photosynthesis. PYO-mediated photocurrents were observed to be 4-fold higher than mediator-free systems with an energetic gain of 200 mV compared to the common high-midpoint potential mediator 2,6-dichloro-1,4-benzoquinone (DCBQ). The low-midpoint potential of PYO led to O2 reduction side-reactions, which competed significantly against photocurrent generation; the tuning of mediator concentration was important for outcompeting the side-reactions whilst avoiding acute cytotoxicity. DCBQ-mediated photocurrents were generally much higher but also decayed rapidly and were non-recoverable with fresh mediator addition. This suggests that the cells can acquire DCBQ-resistance over time. In contrast, PYO gave rise to steadier current enhancement despite the co-generation of undesirable reactive oxygen species, and PYO-exposed cells did not develop acquired resistance. Moreover, we demonstrated that the cyanobacteria can be genetically engineered to produce PYO endogenously to improve long-term prospects. Overall, this study established that energetic gains can be achieved via the use of low-potential phenazines in photosynthetic bioelectrochemical systems, and quantifies the factors and trade-offs that determine efficacious mediation in living bioelectrochemical systems. Phenazines were explored as novel low-midpoint potential molecules for wiring cyanobacteria to electrodes.