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

Abstract 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.