Lipid production by a mixed culture of oleaginous yeast and microalga from distillery and domestic mixed wastewater

Lipid productivity by mixed culture of Rhodosporidium toruloides and Chlorella pyrenoidosa was studied using 1:1 mixed real wastewater from distillery and local municipal wastewater treatment plant with initial soluble chemical oxygen demand (SCOD) around 25,000 mg/L, initial cell density of 2 × 107 cells/mL (yeast) and 5 × 106 cells/mL (microalga), at 30 °C and 2.93 W/m2 (2000 lux, 12:12 h light and dark cycles). Lipid content and lipid yield achieved were 63.45 ± 2.58% and 4.60 ± 0.36 g/L with the associated removal efficiencies for SCOD, total nitrogen (TN), and total phosphorus (TP) at 95.34 ± 0.07%, 51.18 ± 2.17%, and 89.29 ± 4.91%, respectively, after 5 days of cultivation without the pH adjustment. Inoculation of microalgae at 40 h of the initial yeast cultivation and harvesting part of inactive biomass at 72 h by sedimentation could improve both lipid production and wastewater treatment efficiency under non-sterile conditions.