Ability of The Saccharomyces Cerevisiae Y904 to Tolerate and Adapt to High Concentrations of Selenium

Abstract

The rational use of by-products is essential for the development of a sustainable society. Worldwide, the alcoholic fermentation industry generates a large surplus of yeasts, on the scale of millions of tons. So there is a need for beneficial applications to humanity of this surplus. Yeasts, in turn, have the ability to bioaccumulate minerals and enable their bioavailability after cell autolysis. Among these minerals, we highlight selenium (Se), which participates in the formation of antioxidant enzymes. The objectives of the work were to define the minimum and maximum concentration of Se that yeasts (Saccharomyces cerevisiae – Y904) support and the concentrations that they tolerate once adapted. To this end, a test of tolerance to Se was carried out, using treatments with different concentrations of Se. The adaptive process started at the maximum concentration obtained in the tolerance test of 60 µg mL− 1, with an increasing addition of 6 µg mL− 1, reaching up to 246 µg mL− 1 of Se. The macromorphological characteristics and number of colony forming units were evaluated. It was identified that yeasts without adaptation grew on substrate containing up to 60 µg mL− 1 of Se and those adapted, up to 246 µg mL− 1 of Se. In addition to the reduction in yeast growth speed, from the concentration of 84 µg mL− 1 of Se in the medium, morphological changes in colony color were observed. It is concluded that non-adapted yeasts support up to 60 µg mL− 1 of Se and, after the adaptive process, they support 246 µg mL− 1 of Se in the medium.