Effects of selenium on Saccharomyces cerevisiae physiology: essential knowledge for the development of Se-enriched yeast cell factory

Conference poster, 2010

Selenium (Se) is an essential element for many organisms as it is present under the form of Se-cysteine in Se-proteins; furthermore, some bioavailable organic forms of Se have been shown to have anticarcinogenic effects if regularly introduced into the diet. Edible Se-accumulator plants are the main source of Se in the diet; however the level of Se in such plants is highly susceptible to environmental factors and often insufficient to result into beneficial effects. Therefore, the use of Se-enriched yeast as food supplement is made available to avoid Se shortage. The yeast Saccharomyces cerevisiae is able to metabolise and accumulate Se, mainly under the form of selenomethionine. In order to reroute yeast Se metabolic pathways towards the biosynthesis of beneficial Se metabolites, metabolic and bioprocess engineering were necessary and required a deep study on different aspects of yeast physiology in the presence of Se. We present here an array of data that helped in defining the genetic modifications and bioprocess parameters essential to achieve Se-enriched yeast containing bioactive Se-compounds. Data describe how the physiology of S. cerevisiae is influenced by the presence of Se, concerning Se uptake dynamics; interplay between Se and sulphur; induction of oxidative stress; Se- and S-metabolite profile variations under different growth conditions.