Terminal oxidase mutants of the cyanobacterium Synechocystis sp PCC 6803 show increased electrogenic activity in biological photo-voltaic systems
Terminal oxidase mutants of the cyanobacterium Synechocystis sp PCC 6803 show increased electrogenic activity in biological photo-voltaic systems
复制标题
DOI：
10.1039/c3cp52438h
复制
发表时间：
2013-01-01
影响因子：
3.3
通讯作者：
Howe, Christopher J.
中科院分区：
文献类型：
--
作者：
Bradley, Robert W.;Bombelli, Paolo;Howe, Christopher J.
生物光伏系统是一种在阳极采用光合微生物的微生物燃料电池，能够将光能直接转换为电能。与传统微生物燃料电池中发现的厌氧细菌不同，传统微生物燃料电池使用环境中的金属作为终端电子受体，产氧光合生物不适合将电子转移出细胞。产生蓝细菌集胞藻属PCC 6803的突变菌株，其中三种呼吸末端氧化酶复合物的所有组合都已失活。这些菌株进行筛选的能力，以减少膜不可渗透的可溶性电子受体铁氰化物，并将结果进行了比较，在生物光伏系统中的突变体的性能。删除的两个类囊体定位的终端氧化酶，bd-醌醇氧化酶和细胞色素c氧化酶导致在黑暗中的铁氰化物还原率增加了16倍相比，野生型。删除剩余的“替代呼吸末端氧化酶”后，观察到进一步改善，增加了24倍。这些增加反映在生物光伏系统产生的峰值功率上。失活的所有三个终端氧化酶复合物导致大量重定向的还原能力，在黑暗中相当于10%的呼吸电子通量被引导到铁氰化物，相比之下，在野生型不到0.2%。在光照条件下，二氧化碳优先用作电子汇，与野生型相比，铁氰化物还原率只有微小的改善。这项研究表明了优化光合微生物直接电流生产的潜力。
Biological photo-voltaic systems are a type of microbial fuel cell employing photosynthetic microbes at the anode, enabling the direct transduction of light energy to electrical power. Unlike the anaerobic bacteria found in conventional microbial fuel cells that use metals in the environment as terminal electron acceptors, oxygenic photosynthetic organisms are poorly adapted for electron transfer out of the cell. Mutant strains of the cyanobacterium Synechocystis sp. PCC 6803 were created in which all combinations of the three respiratory terminal oxidase complexes had been inactivated. These strains were screened for the ability to reduce the membrane-impermeable soluble electron acceptor ferricyanide, and the results were compared to the performance of the mutants in a biological photovoltaic system. Deletion of the two thylakoid-localised terminal oxidases, the bd-quinol oxidase and cytochrome c oxidase resulted in a 16-fold increase in ferricyanide reduction rate in the dark compared to the wild-type. A further improvement to a 24-fold increase was seen upon deletion of the remaining "alternative respiratory terminal oxidase". These increases were reflected in the peak power generated in the biological photo-voltaic systems. Inactivation of all three terminal oxidase complexes resulted in a substantial redirection of reducing power; in the dark the equivalent of 10% of the respiratory electron flux was channelled to ferricyanide, compared to less than 0.2% in the wild-type. Only minor improvements in ferricyanide reduction rates over the wild-type were seen in illuminated conditions, where carbon dioxide is preferentially used as an electron sink. This study demonstrates the potential for optimising photosynthetic microbes for direct electrical current production.