title: Evaluation of cysteine ethyl ester as efficient inducer for glutathione overproduction in Saccharomyces spp.
abstract: Economical yeast based glutathione (GSH) production is a process that is influenced by several factors like raw material and production costs, biomass production and efficient biotransformation of adequate precursors into the final product GSH. Nowadays the usage of cysteine for the microbial conversion into GSH is industrial state of practice. In the following study, the potential of different inducers to increase the GSH content was evaluated by means of design of experiments methodology. Investigations were executed in three natural Saccharomyces strains, S. cerevisiae, S. bayanus and S. boulardii, in a well suited 50ml shake tube system. Results of shake tube experiments were confirmed in traditional baffled shake flasks and finally via batch cultivation in lab-scale bioreactors under controlled conditions. Comprehensive studies showed that the usage of cysteine ethyl ester (CEE) for the batch-wise biotransformation into GSH led up to a more than 2.2 times higher yield compared to cysteine as inducer. Additionally, the intracellular GSH content could be significantly increased for all strains in terms of 2.29±0.29% for cysteine to 3.65±0.23% for CEE, respectively, in bioreactors. Thus, the usage of CEE provides a highly attractive inducing strategy for the GSH overproduction.
authors.affiliation: Berlin University of Technology, Institute of Biotechnology, 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, Berlin, Germany.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Schmacht
authors.affiliation: Research and Teaching Institute for Brewing in Berlin, Department Bioprocess Engineering and Applied Microbiology, 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; D019149:Bioreactors; D001709:Biotechnology; D001711:Biotransformation; D003545:Cysteine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D005285:Fermentation; D005978:Glutathione / Q000096:biosynthesis*; D012440:Saccharomyces / Q000187:drug effects / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000378:metabolism
chemical_list: C031752:ethyl cysteine; D005978:Glutathione; D003545:Cysteine
keywords: Biotransformation; Cysteine; Cysteine ethyl ester (CEE); Design of experiments (DoE); Glutathione enriched yeast