State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 200237, Shanghai, China.
Bioprocess Biosyst Eng. 2010 Aug;33(6):675-82. doi: 10.1007/s00449-009-0361-6. Epub 2009 Aug 13.
In the present study, permeated yeast cells were used as the catalyst to synthesize glutathione. When waste cells of brewer's yeast were incubated with the three precursor amino acids and glucose for 36 h, 899 mg/L of glutathione were produced. To release the feedback inhibition of gamma-glutamylcysteine synthetase caused by glutathione, two-stage reaction was adopted. In the first stage, glycine was omitted from the reaction mixture and only gamma-glutamylcysteine was formed. Glycine was then added in the second stage, and 1,569 mg/L of glutathione were produced. The conditions of the two-stage reaction were optimized using Plackett-Burman design and response surface methodology. Under the optimized condition, commercially available baker's yeast produced 3,440 mg/L of glutathione in 30 h, and most of the produced glutathione was in the medium. The two-stage reaction could effectively reduce the feedback inhibition caused by glutathione, but degradation of glutathione was significant.
在本研究中，采用渗透酵母细胞作为催化剂来合成谷胱甘肽。当酿酒酵母的废细胞与三种前体氨基酸和葡萄糖孵育 36 小时时，产生了 899mg/L 的谷胱甘肽。为了释放谷胱甘肽对γ-谷氨酰半胱氨酸合成酶的反馈抑制，采用了两阶段反应。在第一阶段，从反应混合物中省略了甘氨酸，仅形成γ-谷氨酰半胱氨酸。然后在第二阶段添加甘氨酸，产生了 1569mg/L 的谷胱甘肽。利用 Plackett-Burman 设计和响应面法优化了两阶段反应的条件。在优化条件下，市售面包酵母在 30 小时内产生了 3440mg/L 的谷胱甘肽，并且大部分产生的谷胱甘肽都在培养基中。两阶段反应可以有效地减轻谷胱甘肽引起的反馈抑制，但谷胱甘肽的降解很明显。
