Hydrolysate from phosphate supplemented sugarcane leaves for enhanced oil accumulation in Candida sp. NG17

Abstract

The objective was to identify yeast NG17, a newly isolated oleaginous yeast obtained from soil in Thailand and to characterize its oil yield and composition in sugarcane leaves hydrolysate (SLH), a sustainable resource. Biochemical and phylogenetic approaches were used to characterize yeast NG17, and its lipid content was determined by gas chromatography. Yeast NG17 was placed in the genus Candida, but not identified to species. It had an oil content of 27.9% (w/w, dry weight) with a major fatty acid composition of oleic (57.6%) and palmitic (25.4%) acids when grown in a high carbon/nitrogen (C/N) ratio medium for 6 d. The oil yield of Candida sp. NG17 was 2.3 g/L when grown in SLH, which contained 18.7 and 19.1 g/L glucose and xylose, respectively, without any supplementation. Meanwhile, the oleic and palmitic acid composition of the oil was reduced to 48.5% and 22.1%, respectively. The oil yield obtained in SLH was higher than that in the detoxified SLH (2.1 g/L). Increasing the SLH pH to 6.5 resulted in an increased oil yield to 5.07 g/L. Supplementation of SLH (pH 6.5) with 0.1% (w/v) KH2PO4 further increased the oil yield of Candida sp. NG17 to 6.67 g/L. Overall, Candida sp. NG17 is a good source of oil for renewable oleochemicals and biodiesel production.