Biomass Production by Antarctic Yeast Strains: An Investigation on the Lipid Composition

Psychrophilic yeast strains Rhodotorula glutinis AL107, Sporobolomyces roseus AL108, Cryptococcus albidus AL55, Cryptococcus laurentii AL56 and Cryptococcus laurentii AL58 isolated from soil sample taken from the region of the Bulgarien base on Livingston Island, Antarctica, were studied. The biomass production was followed after cultivation of the yeasts in a medium with pH 5.3 at 15°C for 120 h. The biomass concentration by psychrophilic yeast strains was: R. glutinis AL107-6.05 g/l, S. roseus AL108-5.78 g/l, Cr. albidus AL55, Cr. laurentii AL56 and Cr. laurentii AL58-6.52 g/l, 6.84 g/l and 6.24 g/l, respectively. The extracted and separated lipids from the samples were supplied to analysis and the compositions of fatty acids, phospholipids, sterols as well as tocopherols were determined. Unsaturated fatty acids, mainly oleic (58.6-63.5%) and of saturated palmitic (18.2-24.5%), predominated in triacylglycerols. Sterols (0.1-0.3%) were valued in the dry yeast biomass. The content of phospholipids, mainly phosphatidylcholine, phosphatidylinositole and phosphatidylethanolamine was found to be in the range of 0.2-1.6%. The quantity of tocopherols was 0-26.3 mg/kg. All of tocopherol classes were established.