Optimization of Biomass and Lipid Production by Yarrowia lipolytica Using Flaxseed and Chia Seed Oils as Substrates

The microbial production of value-added lipids by oleaginous yeasts has attracted considerable interest as a sustainable alternative to conventional lipid sources. In this study, the effects of selected fermentation parameters on biomass production, lipid production, and fatty acid composition of Yarrowia lipolytica YB-423 were investigated using flaxseed and chia seed oils as carbon sources. A Taguchi method was employed to evaluate and optimize the influence of temperature, fermentation time, nitrogen concentration, and oil supplementation. The results showed that nitrogen availability was the dominant factor governing biomass formation. The highest lipid production was achieved at 21 °C after 6 days of fermentation in the absence of an added nitrogen source supplemented with 10 mL/L oil, resulting in lipid contents of 62.53% and 64.61% for flaxseed and chia seed oils, respectively. Lipid content was primarily influenced by nitrogen concentration and oil supplementation, while temperature and fermentation time showed secondary but significant effects. Beyond total lipid production, fatty acid profiling demonstrated that both oil sources supported PUFA-rich lipid production; however, chia seed oil resulted in a broader variation in α-linolenic acid (ALA) content across fermentation conditions. The highest ALA content reached 67.40% at 14 °C after 4 days of fermentation under 30 mL/L chia seed oil supplementation. Additionally, ALA levels reached approximately 62% at 7 °C under higher chia seed oil concentrations (20–30 mL/L). In contrast, flax seed oil yielded relatively stable ALA levels, generally ranging between 45% and 56%, depending on fermentation parameters.