(94b) Cell Lysis, Lipid Recovery, and Lipid Hydroprocessing from Oleaginous Yeast

Single-cell oils, or lipids derived from oleaginous microbes, have seen recent interest as a potential renewable source of transportation fuels. However, one of the main technical challenges involved in single-cell-oil-derived products is the need to lyse the cells and extract the lipids from the resulting complex matrix. We have screened a series of cell lysis approaches using the oleaginous yeast Lipomyces starkeyi, and have found that a dilute acid pretreatment compares favorably to high-pressure homogenization, alkaline pretreatment, bead beating, enzymatic hydrolysis or thermolytic approaches. In particular, acid pretreatment allows recovery of lipids in yields greater than 90% after hexane extraction. We have also shown that the acid pretreatment is effective on strains of Cryptococcus curvatus and Rhodosporidium toruloides, is readily scalable, and the extracted lipids can be hydroprocessed to a renewable diesel blendstock.