New Researches in Biotechnology - Facultatea de Biotehnologii ...

Proceeding of the 4 rd International Symposium“NEW RESEARCH IN BIOTECHNOLOGY” USAMV Bucharest, Romania, 20113. Study of the nitrogen source influenceIn a first step, growth and carotenoids synthesis, including the torularhodin formation withthe Rhodotorula rubra yeast were investigated based on the use of different salts asmineral nitrogen sources such as NH 4 NO 3 , NH 4 H 2 PO 4 , (NH 4 ) 2 SO 4 , NH 4 Cl and NH 4 NO 3 (asthe control salt initially present in MS3 medium) with the concentration of 5 g/L for all thevariants. At the same time for the control medium composition variant the organic nitrogensource, the yeast extract, was supplemented with a concentration of 0.1% from thefollowing amino acids: tryptophan, threonine, glutamic acid, cysteine, alanine, tyrosine,proline, leucine and valine. The experiment lasted for 144 h.The pigments formation results are presented in the fig. 4.Table 1. Experimental variants notation function of the use of different nitrogen sourcesExperimentalNitrogen source,variants5 g/L1 NH 4 NO 3 - control2 NH 4 H 2 PO 43 (NH 4 ) 2 SO 44 NH 4 Cl5 NH4NO3 + 0.1% tryptophan6 NH4NO3 + 0.1% threonine7 NH4NO3 + 0.1% glutamic acid8 NH4NO3 + 0.1% cysteine9 NH4NO3 + 0.1% alanine10 NH4NO3 + 0.1% tyrosine11 NH4NO3 + 0.1% proline12 NH4NO3 + 0.1% leucine13 NH4NO3 + 0.1% valine900m800iued 700m600/L500gµ 400,n 300tio200atr 100cen0noC1 2 3 4 5 6 7 8 9 10 11 12 13Experimental variantsTotal carotenoids concentration as ß-carotene Torularhodin concentrationFig. 4 Variation of the torularhodin concentration, and the total carotenoids concentration (as β-carotene) depending of the nitrogen source from the brothCompared to control medium (MS3) all the variants characterized by small additions ofamino acids have better growths. The introduction of alanine and threonine seems to100