Process for producing glutathione

There is disclosed a fermentation process for producing glutathione which comprises (a) the obtainment of a biomass pre-culture by pre-cultivating, in aerobic conditions, a strain of a glutathione producing yeast wherein the glutathione content per biomass unit is higher than 1.2% w/w; (b) the cultivation, in aerobic conditions, of the resulting biomass pre-culture such that the resulting biomass density is higher than 50 g/l; (c) the activation of the cultured biomass; and (d) the recovery of the cultured biomass, extracting glutathione at a pH equal to or lower than 6 and purifying the resulting glutathione. The process allows to obtain glutathione with high yields and relatively low costs