title: Improvement of oxidized glutathione fermentation by thiol redox metabolism engineering in Saccharomyces cerevisiae.
abstract: Glutathione is a valuable tripeptide widely used in the pharmaceutical, food, and cosmetic industries. In industrial fermentation, glutathione is currently produced primarily using the yeast Saccharomyces cerevisiae. Intracellular glutathione exists in two forms; the majority is present as reduced glutathione (GSH) and a small amount is present as oxidized glutathione (GSSG). However, GSSG is more stable than GSH and is a more attractive form for the storage of glutathione extracted from yeast cells after fermentation. In this study, intracellular GSSG content was improved by engineering thiol oxidization metabolism in yeast. An engineered strain producing high amounts of glutathione from over-expression of glutathione synthases and lacking glutathione reductase was used as a platform strain. Additional over-expression of thiol oxidase (1.8.3.2) genes ERV1 or ERO1 increased the GSSG content by 2.9-fold and 2.0-fold, respectively, compared with the platform strain, without decreasing cell growth. However, over-expression of thiol oxidase gene ERV2 showed almost no effect on the GSSG content. Interestingly, ERO1 over-expression did not decrease the GSH content, raising the total glutathione content of the cell, but ERV1 over-expression decreased the GSH content, balancing the increase in the GSSG content. Furthermore, the increase in the GSSG content due to ERO1 over-expression was enhanced by additional over-expression of the gene encoding Pdi1, whose reduced form activates Ero1 in the endoplasmic reticulum. These results indicate that engineering the thiol redox metabolism of S. cerevisiae improves GSSG and is critical to increasing the total productivity and stability of glutathione.
authors.affiliation: Organization of Advanced Science and Technology, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan.|Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan.
authors.forename: Kiyotaka Y
authors.initials: KY
authors.lastname: Hara
authors.affiliation: Organization of Advanced Science and Technology, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Aoki
authors.affiliation: Organization of Advanced Science and Technology, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan.
authors.forename: Jyumpei
authors.initials: J
authors.lastname: Kobayashi
authors.affiliation: Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, 657-8501, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Kiriyama
authors.affiliation: Organization of Advanced Science and Technology, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan.
authors.forename: Keiji
authors.initials: K
authors.lastname: Nishida
authors.affiliation: Organization of Advanced Science and Technology, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan.
authors.forename: Michihiro
authors.initials: M
authors.lastname: Araki
authors.affiliation: Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, 657-8501, Japan. akondo@kobe-u.ac.jp.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kondo
mesh_terms: D005285:Fermentation; D017353:Gene Deletion; D015870:Gene Expression; D019803:Glutathione Disulfide / Q000378:metabolism*; D005980:Glutathione Reductase / Q000235:genetics / Q000378:metabolism; D005981:Glutathione Synthase / Q000235:genetics / Q000378:metabolism; D060847:Metabolic Engineering; D010084:Oxidation-Reduction; D050862:Oxidoreductases Acting on Sulfur Group Donors / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D013438:Sulfhydryl Compounds / Q000378:metabolism*
chemical_list: D013438:Sulfhydryl Compounds; D050862:Oxidoreductases Acting on Sulfur Group Donors; D005980:Glutathione Reductase; D005981:Glutathione Synthase; D019803:Glutathione Disulfide
keywords: Cell factory; Metabolic engineering; Oxidized glutathione; Saccharomyces cerevisiae; Thiol oxidase; Yeast