The Effect of Intracellular Amino Acids on GSH Production by High-cell-density Cultivation of Saccharomyces cerevisiae
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The present paper studies the effects of precursor amino acids, i.e., l-glutamic acid (Glu), l-glycine (Gly), and l-cysteine (Cys), on the glutathione (GSH) production. The three amino acids were added during the fermentations. The GSH production was analyzed by gas chromatography–mass spectrometry (GC–MS). It was observed that the cell content of Cys reduced continually, Gly maintained a fairly constant concentration, while Glu remained at a high concentration compared with Cys and Gly. The synthesis of GSH was found to significantly increase after 28 h of fermentation upon addition of 6 mmol l−1 of each of the three amino acids. Under these conditions, the GSH yields reached 2,250 ± 50 mg l−1 at 34 h from 1,050 ± 50 mg l−1 at 28 h. The GC–MS analyses on the effect caused by the addition of amino acids indicated that the addition of Glu was not necessary to improve the GSH production by high-cell-density cultivation of Saccharomyces cerevisiae. The addition of Cys or Gly individually enhances the production of GSH.
KeywordsCysteine (Cys) Gas chromatography–mass spectrometry (GC–MS) Glutathione (GSH) Glutamic acid (Glu) Metabolic profiling Saccharomyces cerevisiae
The support obtained from the National “973” Project (no. 2007CB714304 and 2007CB707804), 863 High-Tech Project (no. 2009AA02Z207, 2009AA033001 and 2009AA033002) is highly appreciated.
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