Saccharomyces Cerevisiae Of High-yield Glutathione Fermentation Process Control And Optimization

Glutathione,which is the most abundant non-protein thiol compound, is atripeptide formed by L-glutamic acid, L-cysteine and glycin. GSH presents in the cellsof animals, plants and microorganisms widely.GSH participates in many physiological activities in cells, mainly asanti-oxidants, antidotes and enhance immune function.In recent years, Japanese scientists discovered that GSH had the efficacy toinhibit the AIDS virus. In the food industry, Adding to GSH can not only strengthenthe food flavor, but also be good at the human body. In China, we mainly import GSHfrom Japan, Europe and the United States now. Therefore, by Saccharomycescerevisiae of the high-yield glutathione using inexpensive raw materials fermentproduction of GSH for mass production, we could fill the blank in this area. At thesame time, it could provide with huge social and economic benefits.In this paper, Saccharomyces cerevisiae of high-yield GSH was used as aproduction strain. The first time, in order to reach enhancing the yeast cell volume andintracellular GSH content at the same time, we used two kinds of carbon sources-molasses and glucose by fed-batch fermentation.After adding precursor amino acids, we used the fed-batch cheap glucose toreplace the expensive of ATP, and achieved better results for the first time.We gradually enlarged from250mL shake flask,30L fermenter tank to60M3tank, and achieved a certain economic benefits.In this paper, we studied from the following three baking:1.In the shake flask level, first, fermentation conditions were optimized byorthogonal test. The optimum fermentation conditions was the initial pH5.5,fermentation temperature30℃, shaker speed200rmp/min,shaking bottled liquid25mL/250mL,inoculum10%. Under the best fermentation conditions, we determinedthe best carbon and nitrogen composition of Saccharomyces cerevisiae of thehigh-yield GSH by single factor test. Then, we use Plackett-Burman experimentaldesign, Box-Behnken experimental design and response surface methodology tooptimize the fermentation medium. The best medium was glucose25.95g/L, yeastextract11.47g/L,(NH4)SO410.16g/L, MgSO40.2g/L, KH2PO42g/L.The productionof GSH was170.459g/L, increased40.65%compare with the original124.77mg/L.2.In30L fermenter tank level, with material balance and the design of thefermentation process,we determined to stream molasses the first, then stream glucose.GSH production was increased by16.6%than a single glucose; GSH productionincreased by16.4%than a single molasses in this way3.Adding to precursor amino acid, intracellular GSH yield had a substantialincrease. After adding to precursor amino acids, with detecting the GSH content every6h, it was found that the intracellular GSH content was basic stable when precursoramino acids joined24h, in order to determine the best fermentation time. By studyingthe amount of the precursor amino acids by single factor test, we found that30mmol/L L-glutamic acid,30mmol/L L-Cysteine and18mmol/L glycine was the best amino acid measure. Investigated by the pH of the fermentation lately, the mostsuitable was pH4.5. Then, comparisoned of the ATP and fed-batch glucosefermentation lately, it was feasible that using the flow of cheap glucose insteaded ofthe expensive ATP. Finally, GSH content was43.071mg/g and the production of GSHreached1442.017mg/L by the60M~3fermenter tank on the pilot test after48hfermentation. It was proved that amplification was feasible from the30L fermenter to60M~3fermenter tank.