Papers Abstract

Efficient lipid extraction from the oleaginous yeast Yarrowia lipolytica using switchable solvents
Biodiesel production using oleaginous yeasts, such as Yarrowia lipolytica, has recently attracted strong attention in terms of lipid yield and productivity. However, efficient methods of lipid extraction from oleaginous yeasts are required to further improve the economic feasibility of yeast-based biodiesel production. We investigated the effectiveness of selected switchable hydrophilicity solvents (SHSs), namely, N-ethylbutylamine (EB), N-dipropylamine (DP), and N,N-dimethylcyclohexyl-amine (DMCHA), for lipid extraction from the oleaginous yeast Y. lipolytica. Regardless of using harvested cells or culture broth, DMCHA and EB effectively extracted lipids from Y. lipolytica, resulting in up to 13% higher lipid yields than that obtained by conventional organic solvent extraction using a chloroform/methanol mixture. The lipid extracts obtained by the SHSs showed fatty acid compositions comparable to that obtained with the conventional solvent, thus assuring the quality of biodiesel produced through this method. After switching processes by purging with CO2 and N2, the lipids and solvents were successfully recovered, demonstrating the practicability of lipid extraction using SHSs. Consequently, this study provides an effective lipid extraction method for Y. lipolytica that could significantly improve energy efficiency and economic feasibility of an oleaginous-yeast-based biodiesel production process.