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4 th International Symposium of Biotechnology10 – 11 th November 2011, Bucharest, RomaniaP.III.17. INFLUENCE OF THE CULTURE MEDIUM ONTORULARHODIN PIGMENT BIOSYNTHESISCamelia UNGUREANU 1,2 *, Mariana FERDES 21 University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, Manastur Street 3,400372, Cluj-Napoca, Romania2 University Politehnica of Bucharest, Polizu Street 1, Sector 1, 011061, Bucharest, Romania*ungureanucamelia@gmail.com, +40723239120Keywords: carotenoids, torularhodin, Rhodotorula rubra, β-caroteneThe aim of the present work is to study the formation of the intracellular carotenoidpigment - torularhodin depending on culture medium composition and other cultivation factors.Culture media have a considerable influence on the yeast biomass accumulation andcarotenoid pigments biosynthesis, particularly torularhodin, component with a high-level antioxidantpotential.For all carbon sources tested the Rhodotorula rubra ICCF 209 strain presented a good growth ascan be seen from the OD 600 nm values. The yeast strain growth is stimulated by glucose, fructose,sucrose and maltose, but inhibited by lactose.The studied characteristics – yeast growth, the total carotenoids formation, and thetorularhodin formation recommend the initial pH range of 6-7 as being favorable, the torularhodinratio from the total carotenoids content being greater for the pH of 7.At the same time an inoculum concentration of 1-2 % is favorable for both yeast growth andcarotenoids formation.When NH 4 NO 3 is replaced in the control medium with other mineral nitrogen sources(NH 4 H 2 PO 4 , (NH 4 ) 2 SO 4 , or NH 4 Cl) both the growth and the carotenoids formation are higher whenacid ammonium phosphate was used; in this case a fraction of about 95 % torularhodin is formed inthe pigments mixture.The medium composition variant, where there were both - the replacement of NH 4 NO 3 asanorganic nitrogen source with the same concentration of - NH 4 H 2 PO 4 and the supplementation withalanine (0.1%), threonine (0.2%), and oleic acid (0.1%) – represents the optimum compositionstudied so far for torularhodin formation.Though the growth is not influenced by the temperature change from 28 o C to 30 o C, thecarotenoids formation is influenced for all the medium variants, this indicating a general metabolictrend.The pigments extraction was achieved in n-hexane for total carotenoid pigments and inbasic methanol for torularhodin, the unique acid component.AcknowledgmentsThe work was financially supported by the project POSDRU/89/1.5/S/52432 from 1.04.2010 - Institutionalorganization of a postdoctoral school of national interest "Applied biotechnology with impact in the Romanianeconomy"; the project was cofunded by the EU Social Fund in the framework of the Sectorial OperationalProgramme 2007-2013 for Human Resources Development.65