SYNTHESIS OF GAMMA-LINOLENIC ACID BY MUCORACEOUS FUNGI UTILIZING EXOGENOUS FATTY-ACIDS

The ability of 18 strains of mucoraceous fungi of the genera Mucor, Rh yzopus, and Mortierella to grow and synthesize gamma-linolenic acid on medium containing a mixture of fatty acids as a carbon source was stu died. At 5 g/l of fatty acids in the medium, on the fifth day of growt h, the dry biomass yield of different strains varied from 3.6 to 0.95 g/l, and the portion of gamma-linolenic acid in total cellular fatty a cids, from 1.6% to 9%. With Mucor lusitanicus INMI, growth and lipogen esis were studied at various concentrations of the carbon source in th e medium. At 20 g/l of the fatty acid mixture in the medium, 16.4 g/l of dry biomass accumulated, of which 50% was lipids; gamma-linolenic a cid contributed 5.6% to total cellular fatty acids. When 5 g/l of the fatty acid mixture was added to the medium, the dry biomass yield was 3.6 g/l (10% lipids and 14.7% gamma-linolenic acid). However, when onl y Linoleic acid was used at a concentration of 5 g/l, the biomass yiel d of Mucor lusitanicus was 2 g/l. The fatty acid composition of indivi dual Lipid fractions of Mucor lusitanicus grown on medium containing 1 0 g/l of the fatty acid mixture was also studied. On the fourth day of growth, free cellular fatty acids, polar lipids, and triacylglycerols contained 3.8, 3.47, and 7.84% gamma-linolenic acid, respectively.