Enhancement of glutathione production in Saccharomyces cerevisiae through inverse metabolic engineering

Glutathione is an important tripeptide with a variety of health-promoting effects. Currently, glutathione is produced industrially through a fermentation process using Saccharomyces cerevisiae with high glutathione content. However, the glutathione production yield and titer are relatively low compared to using bacteria as a host strain. The underlying reason for this limitation is that previous studies have mainly focused on gene targets directly related to glutathione production. To overcome this limitation, we aimed to identify novel gene targets capable of enhancing glutathione production in S. cerevisiae. To this end, the #ACR3-12 mutant, exhibiting 1.8-fold higher glutathione content than the wild-type D452-2 strain, was isolated after two rounds of acrolein resistance-mediated screening. Next, the genes responsible for the increased glutathione production were identified by analyzing mutations that occurred in the #ACR3-12 mutant. Notably, the SSD1 and YBL100W-B genes, which encode a translational repressor of cell wall protein synthesis and a Ty2 retrotransposon, respectively, played a crucial role in enhancing glutathione production efficiency. In particular, the D452-2 strain overexpressing the YBL100W-B gene exhibited 1.6- and 2.1-fold higher maximum dry cell weight and glutathione concentration than the wild-type D452-2 strain.