High-glutathione containing yeast Saccharomyces cerevisiae: optimization of production

Experimental design procedure was used to search for optimal medium composition for maximization of glutathione yield using a high-glutathione containing yeast S. cerevisiae S-8H. The effects of the chosen factors (glucose, peptone, KN2PO4, biotin and cysteine) on the relationship between yeast biomass formation and the content of intracellular glutathione were examined. Results obtained showed that glucose and peptone had significant first- and second-order effects, as well as different interactive effects on these overall parameters. On the other hand, cysteine showed only second-order effect for glutathione content and interactive effects for both glutathione content and yield. Its presence had a marked positive effect on the content of glutathione, but reduced the biomass formation. The optimal levels of these factors found were in the range of 2.5%, 4%, 0.027%, 10 micrograms/cm3 and 0.08%, respectively. The average yield obtained at this optimium was 160.1 mg glutathione/dm3 and a glutathione content of 17 mg/g dry biomass.