An unsaturated fatty acid auxotroph derived from the oleaginous yeast Cryptococcus curvatus and named UfaM3 was defective in the conversion of stearic to oleic acid. It was cultivated on diluted (25% prickly-pear juice in batch culture. The carbon to nitrogen ratio (C:N ratio) of the juice (44% glucose and 56% fructose content) was about 50 g/g. Differential utilization of glucose and fructose was observed The efficiency of substrate conversion was 0.50 g/g for biomass and 0.21 g/g for lipids, The quality of lipids produced by UfaM3 approached cocoa butter.