In this work on Rhodotorula gracilis, we studied the level of the representative enzymes of foundamental metabolic ways (HK, PK, G6PDH and IDH) and those of ICL and MS key enzymes of glyoxylate cycle with different carbone sources. The glucose appears the best source of carbone for all the tested enzymes except ICL and MS which are practically absent in the cells developed with this carbone source. In presence of acetate and ethanol we have obtained the expression of the glyoxylate cycle enzymes (ICL and MS). Moreover we obtained the operativity of the glyoxylate cycle in the lipid-rich cells or cells developped on neutral detergents or anionics similar to the fatty acids.