2.2 Genetic transformation of Y. lipolytica
All plasmids constructed were transformed into the Y. lipolyticahost strain Po1g ΔLeu using the lithium acetate/single-strand carrier DNA/PEG method (Chen, Beckerich, & Gaillardin, 1997). And single freshY. lipolytica colonies were picked from YNB selective plates and inoculated into YNB seed media, which were grown at 30 °C for 48 h. For tube test, 100 μL seed cultures were inoculated into 5 mL fermentation media in 50 mL tube. 600 μL seed cultures were inoculated into 30 mL fermentation media in 250 mL shake flasks with 250 rpm and 30 °C. Time series samples were taken for analyzing biomass, sugar content, and squalene titer.