The Promise of Ethylene-Forming Enzymes (EFE) and the Future of Ethylene Production

The rising global demand for petroleum has started the development of infrastructure-compatible, renewable fuels and chemicals. One potentially renewable feedstock that could have an impact is ethylene. There is currently a great interest in developing a technology for ethylene production from renewable resources such as biomass.

Ethylene serves as a building block for a wide variety of plastics, textiles, and chemicals. A process recently has been developed for its conversion into liquid transportation fuels. Ethylene can also be produced biologically, since it is a plant hormone that modulates growth and development, and functions in the defense response to abiotic or biotic stresses. A variety of microbes, including bacteria and fungi, also produce ethylene. One of the metabolic pathways used by these microbes is an ethylene-forming enzyme (EFE). It is a promising biotechnology target since the expression of a single gene is sufficient for ethylene production in the absence of toxic intermediates.

The paper features the first comprehensive review and analysis of EFE, including its discovery, sequence diversity, heterologous expression and reaction mechanism. It also tackles the involvement of EFE in diverse metabolic modes and the requirements for harvesting bioethylene. Strategies that could guide future research directions are also discussed.