Increased campesterol synthesis by improving lipid content in engineered Yarrowia lipolytica

Sterols attract increasing attention due to their important bioactivities. The oleaginous yeast Yarrowia lipolytica has large lipid droplets, which provide storage for the accumulated steroid compounds. In this study, we have successfully constructed a campesterol biosynthetic pathway by modifying the synthetic pathway of ergosterol in Y. lipolytica with different capacity of lipid synthesis. The results showed that the maximal campesterol production was produced in the engineered strain YL-D⁺M^-E^-, as the optimal lipid content. Furthermore, we found that campesterol mainly exists in the lipid droplets. The campesterol production was further accumulated through the overexpression of two copies of dhcr7. Finally, the maximal campesterol production of 837 mg/L was obtained using a 5-L bioreactor in the engineered YL-D⁺D⁺M^-E^-, exhibiting a 3.7-fold increase compared with the initial strain YL-D⁺E^-. Our results demonstrate that the proper promotion of lipid content plays an important role in campesterol biosynthesis in Y. lipolytica, and what we found provides an effective strategy for the production of hydrophobic compounds.Key Points• Campesterol was biosynthesized by deleting erg5 and introducing heterologous dhcr7.• Campesterol production elevated via promotion of lipid content.• Campesterol was mainly found in lipid droplets.• Promotion of lipid content is an effective strategy to produce hydrophobic compounds.