Abstract: The present invention provides for a system comprising: (a) a first nucleic acid encoding an ?-factor receptor operatively linked to a first promoter, (b) a second nucleic acid encoding a recombinase operatively linked to a promoter which is activated by an ?-factor receptor bound to an ?-factor, and (c) a third nucleic acid encoding a gene of interest (GOI) flanked by a pair of recombinase recognition sequences, recognized by the recombinase, operatively linked to a second promoter. The present invention provides for a genetically modified fungal cell comprising the system of the present invention.

Abstract: The present invention generally relates to industrial microbiology, and specifically to the production of biochemical compounds, such as L-serine, L-tyrosine, mevalonate and their derivatives, and recombinant polypeptides using genetically modified microorganisms. More particularly, the present invention pertains to the decoupling of cell growth from production of biochemical compounds, such as L-serine, L-tyrosine, mevalonate and their derivatives, in a microorganism by down regulating the nucleotide biosynthesis in said microorganism.