High-Yield Production of Novel C30 Carotenoids with an Artificial Biosynthesis Pathway in Yarrowia lipolytica.

Traditional microbial research has focused on C40 carotenoids. Recent reports showed that novel C30 carotenoid compounds, found in certain bacterial microorganisms, exhibited antioxidant properties similar to or greater than those of their C40 counterparts. However, the biosynthesis yields were relatively low. In this study, an artificial 8-step pathway for de novo mevalonate biosynthesis in Yarrowia lipolytica was constructed, increasing squalene titer to 1235.79 mg/L. This led to the development of a high-production squalene platform strain capable of supplying sufficient precursors for C30 carotenoid biosynthesis. We identified the low substrate conversion rate as the main limitation through a systematic research. The bottleneck was addressed through protein and compartmentalization engineering, resulting in 90.948 mg/L C30 carotenoid production (11.091 mg/g DCW). Ultimately, by incorporating these approaches, we developed strains capable of producing 2686.77 mg/L C30 carotenoids with a cellular content of 35.05 mg/g DCW in bioreactor fermentations, a significant improvement over the initial strain and the highest ever reported for C30 carotenoids.