title: Medium optimization based on yeast's elemental composition for glutathione production in Saccharomyces cerevisiae.
abstract: The production of glutathione (GSH) or GSH enriched yeast is still in the focus of research driven by a high industrial interest. In this study, an optimal growth rate for GSH production via Saccharomyces cerevisiae Sa-07346 was investigated. To further improve the fermentation process in a way that it is independent of lots, the influence of different WMIX medium compositions on biomass and GSH production was studied. Thereby, the fermentation medium was adjusted based on yeast's elemental composition. The resulting chemically defined fermentation medium led to high cell densities in fed-batches. Therefore, it has the potential to be applied successfully for other high cell density yeast fermentation processes. As cysteine is the key component for GSH production, different cysteine addition strategies were studied and finally, a continuous cysteine feeding was applied in the late stage of fermentation. Thereby, a GSH concentration of 1459 ± 57 mg/l was reached by continuously feeding cysteine, which meant an increase to 253% compared to the control without cysteine addition (577 mg/l GSH).
authors.affiliation: Research and Teaching Institute for Brewing in Berlin, Department Bioprocess Engineering and Applied Microbiology, Seestrasse 13, 13353 Berlin, Germany.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Schmacht
authors.affiliation: Berlin University of Technology, Institute of Biotechnology, Gustav-Meyer-Allee 25, 13355 Berlin, Germany.
authors.forename: Eric
authors.initials: E
authors.lastname: Lorenz
authors.affiliation: Research and Teaching Institute for Brewing in Berlin, Department Bioprocess Engineering and Applied Microbiology, Seestrasse 13, 13353 Berlin, Germany.
authors.forename: Ulf
authors.initials: U
authors.lastname: Stahl
authors.affiliation: Research and Teaching Institute for Brewing in Berlin, Department Bioprocess Engineering and Applied Microbiology, Seestrasse 13, 13353 Berlin, Germany. Electronic address: m.senz@vlb-berlin.org.
authors.forename: Martin
authors.initials: M
authors.lastname: Senz
mesh_terms: D061249:Batch Cell Culture Techniques; D018533:Biomass; D003545:Cysteine / Q000378:metabolism / Q000494:pharmacology; D005285:Fermentation / Q000187:drug effects; D005978:Glutathione / Q000096:biosynthesis*; D012441:Saccharomyces cerevisiae / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism*
chemical_list: D005978:Glutathione; D003545:Cysteine
keywords: A-stat; Cysteine addition; Fed-batch strategy; Flow cytometry; Glutathione enriched yeast; Medium adjustment