Yeast strains that produce steroids independently.

Genetically modified strain of yeast that produces, independently from a simple carbon source, a steroid or steroid derivative, derived from cholesterol metabolism, said steroid being comprised or steroid derivative in the group consisting of pregnenolone, the 17α-hydroxy pregnenolone, cortisol, cortexolone, progesterone, 17α-hydroxy progesterone, and its acetylated derivatives, hydroxylated or containing a halogenated derivative or a methyl group, characterized by inactivation of ATF2 endogenous genes, GCY1 and YPR1.