Quantitative in vivo evaluation of the reverse β-oxidation pathway for fatty acid production in Saccharomyces cerevisiae

Production of fatty acids using engineered Saccharomyces cerevisiae cells is a challenging task in part due to low efficiency of the native fatty acid biosynthesis pathway. One option for improving production efficiency relies on exploring alternative fatty acid production pathways with either improved kinetics, thermodynamics or yield properties.\n\nIn this work, we explored the reverse {beta}-oxidation pathway as an alternative pathway for free fatty acid production. Different gene combinations and analysis methods were tested for assessing pathway efficiency when expressed in the yeast Saccharomyces cerevisiae. Even though different alternatives were tested, quantitative analysis showed no improvement or major change in fatty acid production of the tested strains in our conditions. This lack of improvement suggests that the tested pathway designs and constructs are either nonfunctional in the tested conditions or the resulting strains lack a metabolic driving force that is needed for a functional pathway.\n\nWe conclude that expression of the reverse {beta}-oxidation pathway in S. cerevisiae poses many challenges when compared to expression in bacterial systems. These factors gravely hinder development efforts and success rate for producing fatty acids through this pathway.