engleski

Fatty acid composition of the plasma membrane of baker's and brewer's yeast

Objectives: Determine the fatty acid composition of plasma membrane of two idustrial yeast strains grown under aerobic (baker's yeast) and anaerobic (brewere's yeast) conditions. Methods: Plasma membrtanes were isolated according to Serrano after mechanical disruption of the cell wall using cell homogenizer and glass beads. Proteins were determined by method of Lowry. The quality of the membrane preparations was tested by SDS-Page and Western blotting. Lipids were extracted by Folc method. Fatty acid composition was determined by gas-chromatography of the corresponding methyl esters obtained after acid methanolysis with BF/methanol. results: In the fatty acid composition of baker's yeast plasma membrane saturated fatty acid prevailed (57%), although 18:2 was the main one. The content of 26:0 was surprisingly high (14%). In the plasma membrane of brewers yeast saturated acids prevailed significantly (78%) ; palmitic and stearic acid being the main ones. Conclusions: A significant difference in the fatty acid composition of plasma membrane of two yeasts was found. Low content of unsaturated fatty acid in the plasma membrane of brewer"s yeast is the consequence of anaerobic conditions since the essential step in their biosynthesis 5 oxygen-requiring. High content of 26:0 in the plasma membrane of baker's yeast deseives further invastibations.

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