Establishing Yarrowia lipolytica for aloesone biosynthesis through lipid-metabolism rewiring and carbon-source evaluation

Aloesone is a plant-derived aromatic polyketide that serves as a biosynthetic precursor of aloesin and related glucosides, yet its production in yeast cell factories has not been systematically established. In this study, we reconstructed aloesone biosynthesis in a Yarrowia lipolytica strain pre-optimized for efficient xylose utilization by integrating the aloesone synthase (ALS) gene derived from Rheum palmatum into its genome. LC-MS/MS analysis confirmed the formation of aloesone in the engineered yeast strain, whereas no corresponding signal was observed in the control strain. The ALS overexpressing Y. lipolytica was further modified by deleting diacylglycerol O-acyltransferase and overexpressing peroxisomal biogenesis factor to redirect lipid metabolism and improve precursor availability. The resulting YlALSDP strain produced 393.8 ± 10.18 µg/L aloesone after 96 h of glucose-based cultivation. Further modulation of nitrogen availability increased the titer to 515.0 ± 20.51 µg/L after 105 h, with the highest production obtained under nitrogen-limited conditions. Leveraging the inherent pentose-assimilating capability of the host strain, a comparable titer of 354.55 ± 17.47 µg/L was obtained after 116 h, when xylose was used as an alternative carbon source, suggesting that xylose can also support aloesone biosynthesis in Y. lipolytica . When a mixed carbon source containing 20 g/L glucose and 20 g/L xylose was used, aloesone production reached 436.15 ± 16.76 µg/L after 80 h, further demonstrating the carbon-source flexibility of the engineered strain. Overall, this study establishes a yeast-based platform for aloesone biosynthesis and to our knowledge, provides the first demonstration of Y. lipolytica as a host for aloesone production, laying the groundwork for future optimization of malonyl-CoA-derived plant polyketide production.