Abstract: Glutathione is an important kind of biologically active tripeptides. It is widely used as a pharmaceutical compound and has the potential to be used in food additives and cosmetic industry. The condition of glutathione biosynthesis by Saccharomyces cerevisiae WD-1 in shaking flasks was studied. The effect of medium compositions, including the selection and optimization of carbon source and organic nitrogen source, inorganic salt and cysteine on glutathione production was investigated. The optimal medium was determined as follows: glucose 2%, yeast extract 4%, peptone 2%, NaCl 1%, MgSO₄·7H₂O 0.1%, KH₂PO₄ 0.5%,(NH₄)₂SO₄ 0.2%, Cysteine 2 mmol·L^-1. Orthogonal experiment was carried out in order to determine the optimal conditions, which were as follows: the inoculum size 5%, agitation rate 240 r·min^-1 and the containing liquid 30 mL. In the optimal condition, the glutathione yield achieved 223.22 mg·L^-1,36.81% higher than the initial production．

Key words: glutathione, Saccharomyces cerevisiae, fermentation