Enhanced β-Carotene Production in <i>Yarrowia lipolytica</i> via Co-Utilization of Xylose and Acetic Acid

The coutilization of multiple carbon sources improves metabolic flexibility and efficiency, thereby enhancing product yields while alleviating cellular stress and energy imbalances during biosynthesis. In this study, we engineered <i>Yarrowia lipolytica</i> for enhanced β-carotene production by coutilizing xylose and acetic acid─two major carbon components derived from lignocellulosic hydrolysates. Through the integration of heterologous xylose assimilation pathways, a β-carotene biosynthetic module, the native Acs/Aarc-mediated acetyl-CoA synthesis route, and the nonoxidative glycolysis (NOG) pathway, we established a robust metabolic framework to optimize carbon flux. The engineered strain produced 185.4 mg/L (27.8 mg/g dry cell weight) β-carotene from xylose alone, which was enhanced to 4.2-fold to 776.9 mg/L with a content of 70.4 mg/g dry cell weight under cofermentation with 25 g/L xylose and 25 g/L sodium acetate. These results demonstrate the potential of <i>Y. lipolytica</i> as a versatile microbial chassis for the bioconversion of renewable carbon sources into high-value products, and offer a promising strategy for lignocellulosic biorefinery development through C5-C2 coutilization coupled with NOG pathway enhancement.