[The breeding of high glutathione-producing strain and optimization of culture condition]

High glutathione-producing strain ZJF-71 was constructed by primary screening,isolation of haploid, mutagenesis and protoplasts fusion. The yield of glutathione of the fusant ZJF-71 is 1.59 and 1.42 times that of the parental strains Y64 and Y247, respectively. The factors that affected the biomass and glutathione content of the fusant ZJF-71 were also tested. The highest level of glutathione was obtained in 32 h at 30 degrees C and 200 r/min, when 30 mL of culture in 250- mL shake flasks was incubated in fermentation medium which contained (w/v): 6% cane sugar, 1% peptone, 1% yeast extract, and 2mmol/L cysteine. Glutathione yield under the optimal fermentation condition showed a 2.8-fold improvement over that of the initial condition. The fusant ZJF-71 is stable in genetic by analysis of genetic stability.