Optimization of Culture Conditions for Lipid Production by Rhodosporidium toruloides

The effects of culture conditions on the lipid production by Rhodosporidium toruloides Y4 were investigated using uniform design principles and single-factor experiments. The optimal medium was obtained as follows: 70 g/L glucose, 0.1 g/L (NH4)2SO4, 0.75 g/L yeast powder, 1.5 g/L MgSO4·7H2O, 0.4 g/L KH2PO4, sterilized at 121 °C for 15 min, and then supplemented with 1.91×10−6 mmol/L ZnSO4, 1.50 mmol/L CaCl2, 1.22×10−4 mmol/L MnCl2, and 1.00×10−4 mmol/L CuSO4. The optimal fermentation conditions were also developed as: 50 mL of medium (pH 6.0) in a 250-mL Erlenmeyer flask with 10% inoculum (28-h-old) under orbital shaking at 200 r/min for 120 h at 30 °C. Under the optimized conditions, yeast accumulated lipids up to 76% on a cellular biomass basis with biomass yield of 18.2 g/L.