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Determination of the fatty acids concentration in the cultivation media of a torularhodin producing yeast

Domenii publicaţii > Stiinte ingineresti + Tipuri publicaţii > Articol în volumul unei conferinţe

Autori: Camelia Ungureanu, Ana Aurelia Chirvase, Ligia Alves Da Costa Cardoso, Ivan Marc

Editorial: 2 nd EuCheMS Chemistry Congress, 2008.

Rezumat:

Torularhodin (scheme 1) is the unique carotenoid with a terminal carboxylic group considered now-a-days as a powerful antioxidant to be included in food and drugs formulations.
The improving of this carotenoid formation in an aerobic bioprocess with the red yeast Sporobolomyces ruberrimus, isolated in the National Superior School of Agriculture and Food Industries laboratory, includes the use of technical glycerol, main by-product from the commercial scale biodiesel production, as C source in the cultivation medium. As previous research2 indicated the torularhodin formation is increased function of the fatty acid types and concentration, the purpose of this work was to quantify the fatty acids (palmitic acid, oleic acid, and linoleic acid) concentration in the technical glycerol, and their consume in the cultivation medium during bioprocess.
The analytical procedure to be studied comprised: (a) choice of the method to concentrate the highly diluted fatty acids content (concentration by evaporation at 600C; use of the vacuum concentrator at 450C; lyophilization); (b) the transformation of the fatty acids containing technical glycerol into volatile derivatives by the methyl esterification in view of the Gas Chromatography (GC) quantitative determination3.
Gas Chromatography was performed on a Delsi Nermag DI 200 GC equipped with a flame ionization detector, a capillary injection system, and a silica capillary column, 30m.
(a) Quantitative results demonstrated the lyophilization at -510C during 48 hours and further on hexane extraction was the most appropriate method for fatty acids concentration in the samples.
(b) The composition in fatty acids of the technical glycerol was obtained by the GC analysis performed in the following conditions: vector gas flow-50 ml/min.; injection temperature of 2500C; F.I.D. temperature of 3000C, as being: palmitic acid – C16:0 (27.2 mg/L), oleic acid – C18:1 (244.9 mg/L) and linoleic acid – C18:2 (121.5 mg/L). The yeast growth and torularhodin biosynthesis were positively influenced by the fatty acids from the technical glycerol with the initial concentration of 33,5 g/L in the cultivation medium, but supplemented with 246 μM of stearic acid; the fatty acids were completely consumed in 72 hours of discontinuous bioprocessing in lab reactor.

Cuvinte cheie: Torularhodin, Sporobolomyces ruberrimus, glycerol // Torularhodin, Sporobolomyces ruberrimus, glycerol