Enhancement of lipid productivity of Rhodosporidium toruloides in distillery wastewater by increasing cell density

This study is to improve the process of producing lipid convertible to biodiesel, from distillery wastewater while simultaneously removing organics and nutrients efficiently by inoculating oleaginous yeast Rhodosporidium toruloides in the presence of indigenous microorganisms. The lipid productivity of R. toruloides was studied using real wastewater obtained from distillery and local municipal wastewater treatment plants. Under the conditions of mix rate of 1:1 with domestic wastewater, initial soluble chemical oxygen demand (SCOD) over 20,000 mg/L and initial cell density of 2 × 107 cells/mL at 30 °C, lipid content and lipid yield achieved were 43.65 ± 1.74% and 3.54 ± 0.04 g/L, with the associated removal efficiencies for COD, total nitrogen (TN), and total phosphorus (TP), 86.11 ± 0.41%, 57.81 ± 0.29%, and 67.69 ± 0.73%, respectively, after three days of cultivation in real distillery wastewater without pH adjustment. The pH of wastewater increased from 3.71 to over 8 in 7 days of cultivation.