Engineering Yarrowia lipolytica for high-level ergosterol production

established an artificial proton-dependent pathway, which, together with channel engineering, further increased the titer to 124 mg/L. Lipid droplet engineering and cellular compartmentalization strategies increased the titer to 148.3 mg/L. Ultimately, multi-copy integration of all ergosterol synthesis pathway genes increased the titer to 433.1 mg/L, and fed-batch fermentation in a 5-L bioreactor resulted in a final titer of 4.58 g/L. This study demonstrates a comprehensive hierarchical strategy for high-level sterol production.