Final report : Project : Production of yeast cell oil from sugar cane leaves for biodiesel production

Abstract

The xylose utilizing oleaginous yeasts Cryptococcus humicola NG2, Cyberlindnera subsufficiens NG8.2, Rhodotorula mucilaginosa MG11-2.3 and Yarrowia NG17 were newly isolated. Yarrowia NG17 had the highest accumulated oil content at 27.9% (w/w dry weight; DW) with a major fatty acid composition of oleic (57.6%) and palmitic (25.4%) acids when grown in a high carbon/nitrogen ratio (C/N) medium. Yarrowia NG17 gave a higher oil yield in sugarcane leaves hydrolysate (SLH) than in detoxified SLH, but this was lower compared to in the high C/N medium, while the oleic and palmitic acid compositions were reduced to 48.5% and 22.1%, respectively, in SLH compared to in the high C/N medium. Optimal pH for oil accumulation in SLH was 6.5. Supplementation of SLH (pH 6.5) with 0.1% (w/v) KH2PO4 increased the oil yield of Yarrowia NG17 from 5.07 to 6.67 g/L.