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.
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机译：本文研究了前体氨基酸，即L-谷氨酸（Glu），L-甘氨酸（Gly）和L-半胱氨酸（Cys）对谷胱甘肽（GSH）生产的影响。在发酵过程中添加了三种氨基酸。气相色谱-质谱（GC-MS）分析了谷胱甘肽的产生。观察到，与Cys和Gly相比，Cys的细胞含量持续降低，Gly保持相当恒定的浓度，而Glu保持在高浓度。发现在添加28mmol的三种氨基酸中的每一种后，发酵28小时后，GSH的合成显着增加。在这些条件下，GSH的产量在28小时达到了1,250±50 mg l -1 ，在34小时达到了2,250±50 mg l -1 。 GC-MS对添加氨基酸造成的影响的分析表明，通过高细胞密度酿酒酵母培养，无需添加Glu来提高GSH的产生。单独添加Cys或Gly可提高GSH的产量。
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