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The alcoholic fermentation industry generates a large surplus of yeasts, which, in turn, have the ability to bioaccumulate minerals and enable their bioavailability after cell autolysis. Among these minerals, selenium (Se) stands out, 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 mg mL-1, with increasing addition of 6 mg mL-1, reaching up to 246 mg mL-1 of Se. The macromorphological characteristics and number of colony forming units (CFU) were evaluated. It was identified that yeasts without adaptation grew on substrate containing up to 60 mg mL-1 of Se and those adapted, up to 246 mg mL-1 of Se. In addition to the reduction in yeast growth speed, from the concentration of 84 mg 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 mg mL-1 of Se and, after the adaptive process, they support 246 mg mL-1 of Se in the medium after the adaptive process, which adds value to the final product, and makes yeasts suitable for human nutrition as a supplement or even in the formulation of probiotics.

Brazil is the second-largest producer of ethanol and the alcoholic fermentation wastes have become a concern for both environmental and economic reasons. Recently, the Brazilian industry has implemented the second generation (2G) process to attend the growing for biofuel. In this study, we aimed to investigate whether the 2G vinasse faces the same environmental challenges that first generation (1G) vinasses do, meaning vinasses from ethanol processes using sugarcane juice and/or molasses. Thus, vinasse was obtained from one of the recently-started 2G ethanol facilities in São Paulo State and then chemically characterized. Considering glycerol, mannitol, residual sugars, and organic acids concentrations altogether, it was determined that 2G vinasse had a total carbon source of 23,050 mg L-1 (compared to 4,800 mg L-1 in 1G vinasse). Magnesium, calcium, potassium, and others salts were determined as well. Based on its chemical composition, vinasses could be considered as nutrient sources for other bioprocesses. Finally, we brought some perspectives into bioprocesses with nutritional requirements that might be fully or partially provided by vinasses, leading to the production of bioenergy or bioproducts.

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.

Efeito da suplementação com Sulfato de Ferro (FeSO 4) na vinhaça sobre a produção de biogás versão revisada de acordo com a resolução CoPGr 6018 de 2011