SELECTION OF FATTY-ACID AUXOTROPHS FROM THE OLEAGINOUS YEAST CRYPTOCOCCUS-CURVATUS AND PRODUCTION OF COCOA BUTTER EQUIVALENTS IN BATCH CULTURE

A search was carried out for mutants, defective in the conversion of s tearic acid to oleic acid in effort to improve the quality of lipids p roduced by Cryptococcus curvatus ATCC 20509. Mutants were selected as unsaturated fatty acid (Ufa) auxotrophs. After treatment of parent org anism with Ethyl methanesulfonate (EMS), 11 oleate-requiring auxotroph s were isolated. Only 3 of them were real unsaturated fatty acid (Ufa) mutants, while the other 8 were designated as fatty acid synthetase ( Fas) mutants. The amount of saturated fatty acid (SFA) was about 65.2% in the lipids extracted from on Ufa mutant named UfaM3 and it was sig nificantly higher then that of the wild-type (WT) (46.6%) and similar to that of cocoa butter (60.4%).