Engineering Semi-Artificial Cells for New-to-Nature Photosynthesis

光合作用是由包括植物、藻类和蓝细菌在内的生物体进行的一个古老过程，其中阳光被捕获并转化为能量载体，然后用于合成化学物质。然而，自然的光合作用过程并不是为了效率而进化的。设计更高效和增强的光合作用过程的能力将带来更有前途的可持续清洁（生物）能源生产方式。该项目旨在使用新的生物杂交方法自下而上构建半人工光合细胞，最终展示如何设计细胞以增强或新的自然光合作用。目标是首先分离和修改光合作用的光捕获/电荷传播组分（类囊体），以能够将更多的太阳光谱转化为可用的能量/电荷载体。第二个目标是完全重新编程在蓝藻中发现的强大的CO2浓缩胶囊，称为carboxysomes，通过用更有效的酶取代天然缓慢的CO2转化酶（RUBISCO），可以将质子和CO2转化为有用的原料，包括氢气和甲酸盐。最后一个目标是将两种新的生物杂交组件封装到人工细胞中，以便新的“光反应”可以足够接近，以驱动新的“暗反应”。这一策略将使我们能够了解如何最好地调整光合作用中“光”与“暗”成分的比例，以及任何中间能量载体，以最好地平衡输入和输出通量，并产生最有效的光化学转换系统。这是一种用于工程化光合细胞的高度原创的方法，其将可能产生使用经典合成生物学方法不可能的新的光合效率或化学。这项工作将为未来如何对光合细胞进行生物工程以实现定制性能提供宝贵的经验教训，这将有利于清洁能源以外的几个研究领域，包括农业和生物制造。

Photosynthesis is an ancient process carried out by organisms including plants, algae and cyanobacteria, whereby sunlight is captured and converted to energy vectors that are then used to synthesis chemicals. However, natural photosynthetic processes were not evolved for efficiency. The ability to engineer more efficient and enhanced photosynthetic processes would lead to more promising sustainable ways of clean (bio)energy generation.This project aims to build semi-artificial photosynthetic cells from the bottom up using a new biohybrid approach, to ultimately demonstrate how to engineer cells for enhanced or new-to-nature photosynthesis. The objectives towards this are to firstly isolate and modify the light harvesting/charge propagating component of photosynthesis (the thylakoids) to be able to convert more of the solar spectrum into usable energy/charge carriers. The second objective is to completely reprogram powerful CO2 concentrating capsules found in cyanobacteria, called carboxysomes, by replacing the naturally slow enzyme for CO2 conversion (RUBISCO) with much more efficient enzymes that can turn protons and CO2 into useful feedstocks including hydrogen gas and formate. The last objective is to encapsulate the two new biohybrid components into artificial cells so that the new 'light reaction' can be in close enough proximity to drive the new 'dark reactions'. This strategy will allow us to understand how to best tune the ratios of 'light' to 'dark' components within photosynthesis, as well as any intermediate energy carriers, to best balance the input and output fluxes and give rise to the most efficient light-to-chemical conversion systems. This is a highly original approach for engineering photosynthetic cells that will likely yield new photosynthetic efficiencies or chemistries not possible using classical synthetic biology approaches. This work will provide valuable lessons into how photosynthetic cells can be bioengineered for bespoke performances in the future, which will benefit severl research areas beyond clean energy, including agriculture and bio-manufacturing.