Lipid production from hydrolysate of cassava starch by Rhodosporidium toruloides 21167 for biodiesel making

After the lipid contents in 7 strains of Rhodosporidium toruloides were determined, R. toruloides 21167 among them was found to be able to produce the highest amount of lipid in its cells. Many ions, such as Mn2+, Ca2+, Zn2+ and Fe3+ had positive effects on lipid accumulation by R. toruloides 21167. After the yeast was cultivated in the medium containing 8.0% cassava starch hydrolysate for 144 h at flask level, cell mass, lipid content, residual reducing sugar and residual total sugar in the culture reached 18.5 g m−3, 63.2% (w/w), 15.0 g m−3 and 3.2 g m−3, respectively, while after it was grown in the same medium by 2-l fermentation for 192 h, cell mass, lipid content, residual reducing sugar and residual total sugar in the culture reached 22.0 g m−3, 63.4% (w/w), 5.4 g m−3 and 0.5 g m−3, respectively. The results also showed that most of the sugar added to the medium was utilized by R. toruloides 21167 for cell growth and lipid accumulation. Over 96.8% of the fatty acids from the yeast strain 21167 was C16:0, C18:0, C18:1 and C18:2, especially C18:1 (53.34%). The biodiesel obtained from the produced lipid could be burnt well.