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

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.