Abstract
Background: Microorganisms including yeasts that are capable of accumulating lipids above 20 to 70% of their dry biomass are collectively named oleaginous. The oil produced from such microorganisms can be used as alternative sources of oils for human consumption, feedstocks for production of biodiesel, components in paints, coatings, detergents, cleaning products, cosmetics, plastics, rubber and intermediate products.Results: In this study Cutaneotrichosporon curvatus (Cryptococcus curvatus) PY39, an oleaginous yeast, isolated from flower surface in Ethiopia, was grown under nitrogen-limited media. The capacity of this strain with respect to biomass production, lipid yield and lipid content was evaluated. To determine the optimal culture conditions for this oleaginous yeast, different carbon and nitrogen sources, carbon to nitrogen (C/N) ratio, pH, incubation temperature, shaking speed and incubation period were investigated. The optimal fermentation conditions were obtained as follows: 70 g/L of glucose as carbon source; combinations of ammonium sulphate and yeast extract as nitrogen sources at, respectively, 0.50 g/L and 0.47 g/L; initial pH of 5.0; temperature at 30oC, shaking speed of 225 rpm, and cultivated for 144 h. Under the optimized conditions, C.curvatus PY39 accumulated lipids up to 7.22±0.26 g/L on dry biomass basis. Such values correspond to lipid content of 48.66±0.60%. This strain was further grown on media containing peel mixtures of papaya and mango. Under the optimized conditions, C. curvatus PY39 exhibited a lipid yield and lipid content of 3.95±0.67 g/L and 35.02±1.63%, respectively. The fatty acid profiles were analyzed using gas chromatography. Data revealed the presence of significant amount of oleic acid (54.40±1.15%), palmitic acid (17.39±0.47%), stearic acid (13.16±0.93%) and low amount of other fatty acids in the extracted yeast oils which indicate that the fatty acid profiles were very similar to that of conventional vegetable oils.Conclusion: The results of fatty acid profiles showed that the microbial lipids from the studied yeast can be good feedstocks for biodiesel production.
Draft Genome Sequence of the Oleaginous Yeast
Cryptococcus curvatus
ATCC 20509
