NREL Partnership: Engineering synthetic RNA devices to expediate the evolution of metabolite producing micro-organisms

乙烯是一种小分子碳氢化合物气体，广泛应用于化学工业。其全球年产量目前超过1.5亿吨，超过任何其他有机化合物。目前，乙烯是通过乙烷的蒸汽裂解产生的，这会产生大量的二氧化碳，导致全球变暖。乙烯是最常见的塑料、聚乙烯的单体，全球年产量约为8000万吨。因此，开发一种可持续的或碳中性的乙烯生产替代品势在必行。铜绿假单胞菌是一种革兰氏阴性土壤细菌，能够在二氧化碳上生长，从而能够在对环境影响最小的情况下生产低碳燃料和化学品。该项目的目的是将Cupriavidus Necator设计为生产乙烯等碳氢化合物产品的平台。目前有三种乙烯合成途径。该项目将重点介绍在丁香假单胞菌和指状青霉中发现的替代途径，该途径利用α-酮戊二酸(AKG)和精氨酸在乙烯形成酶(EFE)催化的反应中进行。将利用微生物工程将通量重新定向到乙烯生产。合成生物学中的一个潜在问题仍然是用于构建遗传电路的可组合、高性能部件的数量有限，以及将多个组件集成到一个大型、复杂的合成网络中时出现的困难，该项目将利用基于RNA的调控元件作为这一组件瓶颈的潜在解决方案。我们将利用尖端从头设计的称为Toehold Switches的核转录调节器，将人造sRNA作为菌株改良的平台，这些系统通常能够对蛋白质表达进行超过两个数量级的调节，并已在大肠杆菌中验证了100多个功能系统。随着RNA在合成生物学的未来中继续发挥重要作用，合成RNA在调节和结构应用方面的使用正处于上升轨道上。通过结合诺丁汉大学SBRC和NREL各自的优势，有真正的机会在以细菌为基础的从生物质中获得化学品和燃料的新路线方面取得重大进展。

Ethylene is a small hydrocarbon gas, widely used in the chemical industry. Its annual worldwide production currently exceeds 150 million tonnes, surpassing any other organic compound. Ethylene is currently produced from steam cracking of ethane which produces vast quantities of CO2, contributing to global warming. Ethylene is the monomer for the most common plastic, polyethylene, and annual global production is approximately 80 million tons. Therefore, unlocking a sustainable or carbon neutral alternative to ethylene production is imperative. Cupriavidus necator is a Gram-negative soil bacterium, capable of growing on CO2 enabling low carbon fuels and chemicals to be produced with minimal environmental impact. The aim of this project being to engineer Cupriavidus necator as a platform for the production of hydrocarbon-based products such as ethylene. There are currently three pathways for ethylene synthesis this project will focus on the alternative pathway found in Pseudomonas syringae and Penicillium digitatum, which utilises a-ketoglutarate (AKG) and arginine in a reaction catalyzed by the ethylene-forming enzyme (EFE). Microbial engineering will be utilised to redirect flux towards ethylene production. An underlying problem in synthetic biology remains the limited number of composable, high-performance parts for constructing genetic circuits and difficulties that arise when integrating multiple components into a large, complex synthetic network, the project will utilise RNA-based regulatory elements as a potential solution to this component bottleneck. We will engineer artificial sRNAs as a platform for strain improvement utilising cutting edge de-novo designed riboregulators termed toehold switches, these systems routinely enable modulation of protein expression over two orders of magnitude and have validated over 100 functional systems in E. coli. The use of synthetic RNA, for both regulatory and structural applications, is on an upward trajectory as RNA continues to play an important role in the future of synthetic biology. By combining the respective strengths of Nottingham University SBRC and the NREL, there is a real opportunity to make significant progress towards new bacterial-based routes to chemicals and fuels from biomass.