Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo, 657-8501, Japan.
Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52‑1 Yada, Suruga‑ku, Shizuoka, 422‑8526, Japan.
Microb Cell Fact. 2022 Aug 6;21(1):153. doi: 10.1186/s12934-022-01880-8.
Glutathione is a valuable tri-peptide that is industrially produced by fermentation using the yeast Saccharomyces cerevisiae, and is widely used in the pharmaceutical, food, and cosmetic industries. It has been reported that addition of L-serine (L-Ser) is effective at increasing the intracellular glutathione content because L-Ser is the common precursor of L-cysteine (L-Cys) and glycine (Gly) which are substrates for glutathione biosynthesis. Therefore, we tried to enhance the L-Ser biosynthetic pathway in S. cerevisiae for improved glutathione production.
The volumetric glutathione production of recombinant strains individually overexpressing SER2, SER1, SER3, and SER33 involved in L-Ser biosynthesis at 48 h cultivation was increased 1.3, 1.4, 1.9, and 1.9-fold, respectively, compared with that of the host GCI strain, which overexpresses genes involved in glutathione biosynthesis. We further examined simultaneous overexpression of SHM2 and/or CYS4 genes involved in Gly and L-Cys biosynthesis, respectively, using recombinant GCI strain overexpressing SER3 and SER33 as hosts. As a result, GCI overexpressing SER3, SHM2, and CYS4 showed the highest volumetric glutathione production (64.0 ± 4.9 mg/L) at 48 h cultivation, and this value is about 2.5-fold higher than that of the control strain.
This study first revealed that engineering of L-Ser and Gly biosynthetic pathway are useful strategies for fermentative glutathione production by S. cerevisiase.
谷胱甘肽是一种有价值的三肽，可通过使用酵母酿酒酵母（Saccharomyces cerevisiae）进行发酵工业生产，广泛应用于制药、食品和化妆品行业。据报道，添加 L-丝氨酸（L-Ser）可有效增加细胞内谷胱甘肽含量，因为 L-Ser 是 L-半胱氨酸（L-Cys）和甘氨酸（Gly）的共同前体，是谷胱甘肽生物合成的底物。因此，我们试图增强酿酒酵母中的 L-Ser 生物合成途径，以提高谷胱甘肽的产量。
与宿主 GCI 菌株（其过量表达参与谷胱甘肽生物合成的基因）相比，单独过表达参与 L-Ser 生物合成的 SER2、SER1、SER3 和 SER33 的重组菌株在 48 h 培养时的谷胱甘肽体积产量分别提高了 1.3、1.4、1.9 和 1.9 倍。我们进一步研究了使用重组 GCI 菌株（其过表达 SER3 和 SER33）作为宿主同时过表达分别参与 Gly 和 L-Cys 生物合成的 SHM2 和 CYS4 基因。结果，过表达 SER3、SHM2 和 CYS4 的 GCI 显示出最高的谷胱甘肽体积产量（64.0±4.9mg/L），在 48 h 培养时，这一值比对照菌株高约 2.5 倍。
本研究首次表明，工程化 L-Ser 和 Gly 生物合成途径是通过酿酒酵母发酵生产谷胱甘肽的有用策略。
