Screening,Identification and Cultural Condition Optimization of Glutathione-Producing Insect-Symbiotic Yeast

A reduced form glutathione(GSH) producing yeast strain SM3 was isolated from the intestine of pond skater(Aquarlus elongatus),and it was identified initially as Candida carpophila.The cultural substrates for the strain to produce GSH were optimized by orthogonal experiment with the components as follows: 3% sucrose as carbon source,0.2%(NH 4) 2 SO 4 as inorganic nitrogen source,0.8% yeast extract as organic nitrogen source,0.3% K 2 SO 4,0.6% KH 2 PO 4,0.15% MgSO 4.The single-factor experiments showed the optimized fermentation conditions were as follow: inoculation amount at 15%,culture for 36 h,filling volume at 20 /250 mL,shaking at 200 r / min,temperature and pH were at 32 ℃ and 6.0 respectively.The GSH yield was as high as 159.35 mg / L after the optimization,increased by 105.27% as compared with that before optimization.