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

太阳能是一种可持续发展的资源，超过了预测的人类能源需求30个数量级。如果这种漫射的太阳能能够被有效地集中和储存，那么它就有能力提供未来人类的能源需求。氧化光合作用的过程，即光自养生物利用光和水减少二氧化碳的过程，将太阳能储存在还原的碳化合物中，这是对社会有用的燃料。虽然氧化光合作用在大约35亿年前就已经进化出来了，但它在将太阳能转化为化学能并最终转化为生物质能方面仍然效率低下。商业光伏电池与电解槽一起分解水，以大约10%的效率生产氢气。在最佳条件下，植物的光合作用产量通常不超过1%，而产量较高的微藻物种估计有3%的效率。在大多数情况下，生物将光转化为储存的化学能不受光的限制，而是受碳还原速度的限制。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”的光合能力提供替代途径。我们的策略是设计一个细胞间即插即用平台（PNP），使我们能够将电子和/或减少的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，从而绕过固有的低效碳固定催化剂RuBisCO。这一目标的实现需要对光合作用的基础生物学进行根本性的操作，并开发新的合成生物、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.