Pseudomonas putida uses cheap plant biomass as a carbon source to make isoprenol
The Science: Sustainable aviation fuels made from renewable carbon sources have the potential to reduce CO2 emissions and mitigate climate change. Isoprenol, a precursor to the biojet fuel blendstock known as 1,4-dimethylcyclooctane (DMCO), has emerged as an important target. Isoprenol has been produced in several microbial hosts, but it would be beneficial to sustainable aviation fuel efforts if isoprenol could be made in microorganisms that use fermentable sugars liberated from lignocellulosic biomass as a carbon source. Pseudomonas putida could be such a microorganism, but there is still work to be done to make it the optimal host. In this work, researchers engineered P. putida for isoprenol production using advanced computing tools.
The Impact: Researchers used computational modeling approaches to predict gene knockout targets and optimize a metabolic pathway in P. putida that maximized isoprenol production. Their approach allowed them to select and prioritize gene knockout targets and therefore test a smaller number of engineered strains. They were able to achieve a 3.5 g/L production titer, the highest reported for P. putida. This research makes progress on developing a bioproduction process that can use renewable carbon sources.
Summary: The researchers used a mixture of computational modeling and strain engineering to optimize isoprenol production in P. putida. They used multiple genome-scale metabolic model-based approaches to predict and prioritize gene knockout targets that would lead to increased isoprenol yields. This allowed them to reduce the number of targets they pursued. In addition, they applied known genetic edits to further improve isoprenol production and used proteomics to optimize the process. They concluded that their pathway optimization resulted in a 10-fold improvement of isoprenol in P. putida. The researchers suggest additional improvements must be made to improve isoprenol yields for industrial applications. Improvements such as the inclusion of CRISPR gene editing and other bioprocess technologies are still needed to produce isoprenol and DMCO at commercial scale.
Publication: Banerjee, D., Yunus, I., Wang, X., et al. Genome-scale and pathway engineering for the sustainable aviation fuel precursor isoprenol production in Pseudomonas putida. Metabolic Engineering (2024). [DOI: 10.1016/j.ymben.2024.02.004]
Written by Emily Nelson