Anthropogenic carbon dioxide (CO2) release in the atmosphere from fossil fuel combustion has inspired scientists to study CO2 to fuel conversion. Oxygenic phototrophs such as cyanobacteria have been used to produce biofuels using CO2. However, oxygen generation during oxygenic photosynthesis affects biofuel production efficiency. To produce n-butanol (biofuel) from CO2, here we introduced an n-butanol biosynthesis pathway into an anoxygenic (non-oxygen evolving) photoautotroph, Rhodopseudomonas palustris TIE-1 (TIE-1). Using different carbon, nitrogen, and electron sources, we achieved n-butanol production in wild-type TIE-1 and mutants lacking electron-consuming (nitrogen-fixing) or acetyl-CoA-consuming (polyhydroxybutyrate and glycogen synthesis) pathways. The mutant lacking the nitrogen-fixing pathway produced highest n-butanol. Coupled with novel hybrid bioelectrochemical platforms, this mutant produced n-butanol using CO2, solar panel-generated electricity, and light, with high electrical energy conversion efficiency. Overall, this approach showcases TIE-1 as an attractive microbial chassis for carbon-neutral n-butanol bioproduction using sustainable, renewable, and abundant resources.

中文翻译：

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假单胞菌TIE-1可持续生产生物燃料正丁醇

化石燃料燃烧在大气中释放的人为二氧化碳（CO2）启发了科学家们研究二氧化碳到燃料的转化。诸如蓝细菌的产氧营养养分已被用于利用二氧化碳生产生物燃料。但是，在氧气光合作用过程中产生的氧气会影响生物燃料的生产效率。为了从CO2中生产正丁醇（生物燃料），在这里，我们将正丁醇生物合成途径引入了一种无氧（无氧进化）光合自养生物，Rhodopseudomonas palustris TIE-1（TIE-1）。使用不同的碳，氮和电子源，我们在野生型TIE-1和缺少电子消耗（固氮）或乙酰辅酶A（聚羟基丁酸酯和糖原合成）途径缺乏的突变体中实现了正丁醇的生产。缺少固氮途径的突变体产生最高的正丁醇。结合新型的混合生物电化学平台，该突变体利用二氧化碳，太阳能电池板产生的电和光产生了正丁醇，具有很高的电能转换效率。总体而言，这种方法将TIE-1展示为一种有吸引力的微生物底盘，可利用可持续，可再生和丰富的资源进行碳中性正丁醇生物生产。