The present invention describes a process comprising a) subjecting a microorganism to autolysis under conditions at which a substantial part of the RNA remains in a form degradable into 5-ribonucleotides; b) subjecting the autolysate to solid/liquid separation and recovering the RNA-containing cell wall fraction; and c) converting the RNA in the recovered RNA-containing cell wall fraction into 5- ribonucleotides, whereby the solid/liquid separation in step b) is done at a pH of lower than 5.1. Said process is simple and allows for the production of a very pure composition of 5'-ribonucleotides. It also allows for the production of a very clear yeast extract.