Systematic Metabolic Engineering and Fermentation Optimization of Yarrowia lipolytica for High-Yield Production of Scutellarin

Scutellarin, a flavonoid glycoside with anti-inflammatory, antioxidant, and cerebral/myocardial ischemia-ameliorating activities, is currently sourced from plants; however, this method is limited by high cultivation costs and low yields. In this study, de novo biosynthesis of scutellarin was achieved through systematic metabolic engineering of Yarrowia lipolytica . First, fusion of the key enzyme SbF6H with ATR2 (Sl1A) enhanced catalytic efficiency by 12.57%. Next, adding a solubility-enhancing tag to FNS I increased scutellarin titer by 44.33%. Subsequently, a xylose-inducible system coupregulated FNS I and Sl1A, while precursor supply was enhanced via metabolic rewiring. The resulting strain produced 1,184.24 mg/L in shake flasks; fed-batch fermentation in a 5-L bioreactor reached 6,370.39 mg/L, which is the highest microbial titer reported to date, with only 7.26% byproduct. This work establishes a scalable platform for industrial scutellarin production and provides a generalizable framework for microbial synthesis of high-value flavonoids.