Expanding the metabolism of the most primitive phototroph

碳固定和转化为碳水化合物是自然界中占主导地位的生化过程之一，为所有生物体提供细胞构建模块。这种固定或全球初级生产力的大部分是由陆地上的植物和海洋环境中的藻类和蓝细菌利用卡尔文循环进行的，再加上阳光转化为化学能。这个过程产生了允许地球上复杂生命进化的环境条件。然而，化石燃料排放的释放速度正在破坏大气中微妙的气体平衡，导致全球变暖和气候崩溃。除了减少温室气体排放外，还必须开发新技术，从环境中捕获二氧化碳并将其储存为有机化合物，为此必须探索有效的生物途径。在遍布生命之树的微生物中发现了替代的碳固定途径。其中最古老的是伍德-永达尔途径，仍然被发现居住在缺氧环境中的厌氧细菌和古生菌所使用。这一途径是最简单、最节能的二氧化碳捕获途径。有趣的是，最原始的光养生物，厌氧的太阳菌，不能固定碳，但它们与使用伍德-扬达尔途径作为碳源的细菌密切相关。该合成生物学项目旨在将高效节能的CO2固定与太阳菌光合生产ATP相结合，为碳捕获和储存提供令人兴奋的前景。所确定的原则将直接适用于可再生化学品的可持续生产。

Carbon fixation and conversion into carbohydrate is one of the dominant biochemical processes in nature, supplying the cellular building blocks for all living organisms. The majority of this fixation, or global primary productivity, is performed by plants on land and by algae and cyanobacteria in marine environments using the Calvin cycle, coupled to the conversion of sunlight into chemical energy. This process has produced the environmental conditions that permitted the evolution of complex life on Earth. However, the rate of release of fossil fuel emission is disrupting the delicate gas balance of the atmosphere, leading to global warming and climate breakdown. Beyond cutting greenhouse gas emissions, it is essential that new technologies are developed to capture CO2 from the environment and store it as organic compounds, for which efficient biological routes must be explored.Alternative carbon fixation pathways are found in microbes dispersed throughout the tree of life. The most ancient of these, the Wood-Ljungdahl pathway, is still used by anaerobic bacteria and archaea found inhabiting environments lacking oxygen. This pathway is the simplest and most energy-efficient route for CO2 capture. Interestingly, the most primitive phototrophs, the anaerobic Heliobacteria, are unable to fix carbon, but they are closely-related to bacteria that use the Wood-Ljungdahl pathway as a source of carbon. This synthetic biology project aims to couple energy-efficient CO2 fixation to phototrophic generation of ATP in Heliobacteria, providing an exciting prospect for carbon capture and storage. The principles defined will be directly applicable to the sustainable generation of renewable chemicals.