14-PSIL: Plug and Play Photosynthesis for RuBisCO Independent Fuels

太阳能是一种可持续的资源，超过预测的人类能源需求>3个数量级。如果这种分散的太阳能可以有效地集中和储存，那么它就有能力满足未来人类的能源需求。氧化光合作用的过程，即光合自养生物利用光和水还原CO2，将太阳能储存在还原的碳化合物中，这些碳化合物是社会有用的燃料。尽管氧化光合作用在大约35亿年前就已经进化出来，但它在将太阳能转化为化学能并最终转化为生物质方面仍然效率低下。商业光催化剂与电解器一起分解水，以大约10%的效率产生氢气。在最佳条件下，植物的光合产量通常不超过1%，而高产微藻物种的效率估计为3%。在大多数条件下，光到储存的化学能的生物转化不受光的限制，而是受碳还原速率的限制。该项目的目标是设计将光合能量从线性电子流（LEF）转移到替代汇的途径，从而在碳固定饱和时为“过剩”光合能力提供替代途径。我们的战略是设计一个细胞间的即插即用平台（PNP），使我们能够将电子和/或还原化学物质从改良的光合源细胞转移到独立设计的燃料生产模块，绕过固有的低效碳固定催化剂RuBisCO。这一目标的实现将需要对光合作用的基础生物学进行彻底的操纵，并开发新的合成生物学、化学和分析技术。

Solar energy is a sustainable resource exceeding predicted human energy demands by >3 orders of magnitude. If this diffuse solar energy can be concentrated and stored efficiently, then it has the capacity to provide for future human energy needs. The process of oxidative photosynthesis, namely the reduction of CO2 utilizing light and water by photoautotrophs, stores solar energy in reduced carbon compounds, which are useful fuels for society. Although oxidative photosynthesis evolved some 3.5 billion years ago, it remains inefficient at converting solar energy into chemical energy and, ultimately, biomass. Commercial photovoltaics in concert with electrolyzers split water to produce hydrogen at an efficiency of approximately 10%. Photosynthetic yields for plants in optimal conditions typically do not exceed 1%, and higher-yielding microalgae species are estimated to have 3% efficiency. Under most conditions, the biological transformation of light to stored chemical energy is not limited by light but by the rate of carbon reduction. The goal of this project is to engineer pathways for diverting photosynthetic energy from linear electron flow (LEF) to alternative sinks, thereby providing alternate routes for "excess" photosynthetic capacity when carbon fixation is saturated. Our strategy is to engineer an intercellular, plug-and-play platform (PNP) that allows us to move electrons and/or reduced chemicals from modified photosynthetic source cells to independently engineered fuel-production modules that bypass the inherently inefficientcarbon-fixing catalyst RuBisCO. The realization of this goal will require radical manipulation of the fundamental biology of photosynthesis and development of novel synthetic biological, chemical, and analytical techniques.