Engineering central metabolism in Yarrowia lipolytica increases lipid accumulation

Yarrowia lipolytica, a non-conventional oleaginous yeast, holds great promise for a wide range of metabolic engineering applications. Strains of this species are renowned for their capacity to accommodate high carbon flux through acetyl-CoA and are, therefore, being extensively studied for producing chemicals derived from this precursor molecule. We investigated the effects of the pyruvate bypass, phosphoketolase bypass, and the carnitine shuttle on Y. lipolytica’s central carbon metabolism by monitoring the production of lipids and β-carotene. We constructed a set of parental strains derived from the Y. lipolytica YB-392 wild-type strain, introduced the metabolic bypasses, and subjected the constructed strains to a series of fermentation experiments. We discovered that upon introducing the modifications to central carbon metabolism, carbon is preferentially directed through the lipid biosynthesis pathway, making such engineering an effective strategy for increasing lipid production. The highest lipid content of 0.61 g_lipids/g_DCW was recorded after introducing the carnitine shuttle-associated gene YlCAT2. Meanwhile, the highest increase in production efficiency, 78.2 %, was recorded for a combination of genes associated with the pyruvate bypass (YlPDC1, YlALD3, YlACS1).