Engineering Yarrowia lipolytica for enhanced lipid productivity in nutrient-rich conditions: A scalable approach to microbial lipid production.

Climate change is reducing crop yields and increasing price volatility for commodities like cocoa and palm oil, thereby driving the need for sustainable alternatives such as microbial lipid production. The oleaginous yeast Yarrowia lipolytica is a promising platform for lipid synthesis. However, its lipid accumulation has traditionally relied on nitrogen limitation, posing challenges for achieving high yields under nutrient-rich conditions. In this study, we engineered Y. lipolytica to enhance lipid accumulation and productivity in nutrient-rich environments. Key modifications included deleting MHY1 to prevent filamentous growth, overexpressing triacylglycerol (TAG) biosynthetic genes, disrupting fatty acid degradation, and redirecting phosphatidic acid flux toward TAG biosynthesis by reducing phospholipid production through OPI3 deletion and CDS1 mutation. Furthermore, deletion of CEX1 to block citrate excretion significantly enhanced lipid accumulation. The resulting strain, CJ0415, achieved a lipid production of 54.6 g/L with a lipid content of 45.8 % and a record lipid productivity of 2.06 g/L/h under nutrient-rich conditions in a 5-L fermenter, representing a 2.6-fold increase compared to nitrogen-limited conditions. These findings underscore the potential of Y. lipolytica as a robust platform for scalable, industrial lipid production under nutrient-rich conditions.