Engineering improved ethylene production: Leveraging systems biology and adaptive laboratory evolution

Ethylene is a small hydrocarbon gas widely used in the chemical industry. Annual worldwide production currently exceeds 150 million tons, producing considerable amounts of CO2 contributing to climate change. The need for sustainable alternative therefore imperative. natively produced by several different microorganisms, including Pseudomonas syringae pv. phaseolicola via process catalyzed ethylene-forming enzyme (EFE), subsequent heterologous expression EFE has led ethylene non-native bacterial hosts Escherichia coli and cyanobacteria. However, solubility substrate availability remain rate-limiting steps biological production. We employed combination genome-scale metabolic modelling, continuous fermentation, protein evolution enable accelerated development high efficiency E. strain, yielding 49-fold increase production, most significant improvement reported date. Furthermore, we have clearly demonstrated that this increased yield resulted from adaptations were uniquely linked (wild type versus mutant). Our findings provide novel solution deregulate bottlenecks key pathways, which can be readily applied address other engineering challenges.