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<p>Spent yeast represents a promising opportunity for value-added applications. This study proposes its biofortification as a source of organic selenium (Se)-enriched supplements. Se is an essential component of the glutathione (GSH) system, playing a critical role in decomposing lipid peroxidation products and protecting cellular membranes. We evaluated the effects of sodium selenite (Na₂SeO₃) supplementation on enzymatic activity, oxidative stress markers, and biomass production of <i>Saccharomyces cerevisiae</i> Thermosacc<sup>®</sup>, cultivated in corn hydrolysate—a non-synthetic medium that provides a more realistic representation of industrial environments—under aerobic and anaerobic conditions. Antioxidant responses were assessed via glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione S-transferase (GST) activities, while oxidative stress was measured through hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) levels. Yeasts were grown with 0, 200, and 400&#xa0;mg L<sup>−1</sup> Na₂SeO₃. The highest enzymatic activities were observed in AE400 (GPx: 5.35&#xa0;μmol&#xa0;mg<sup>−1</sup>, GR: 3.39&#xa0;μmol&#xa0;mg<sup>−1</sup>, GST: 0.035&#xa0;μmol&#xa0;mg<sup>−1</sup>), indicating enhanced antioxidant defenses under aerobic Se supplementation. However, increased Se concentrations also elevated H₂O₂ and MDA levels—especially in aerobic conditions—likely due to intensified ROS generation. Consequently, biomass production and growth parameters declined, suggesting an energy trade-off in which antioxidant defense is prioritized over cell proliferation. These findings highlight Se’s dual role as both an antioxidant and a pro-oxidant at elevated concentrations. This study advances understanding of yeast redox biology and supports the integration of Se-enriched yeast production into industrial fermentation as a sustainable strategy for generating high-value functional ingredients for food and feed applications.</p>

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Selenium-biofortified spent yeast cultivated in corn hydrolysate: antioxidant response and biomass production under aerobic and anaerobic conditions

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2025年10月14日

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  • Layna Amorim Mota,
  • Rubens Perez Calegari,
  • Alana Uchôa Pinto,
  • Pietro Sica,
  • Deoclecio Jardim Amorim,
  • Ricardo Antunes Azevedo,
  • Salete Aparecida Gaziola,
  • Rafael Soares Douradinho,
  • Antonio Sampaio Baptista,
  • Valter Arthur

摘要

Spent yeast represents a promising opportunity for value-added applications. This study proposes its biofortification as a source of organic selenium (Se)-enriched supplements. Se is an essential component of the glutathione (GSH) system, playing a critical role in decomposing lipid peroxidation products and protecting cellular membranes. We evaluated the effects of sodium selenite (Na₂SeO₃) supplementation on enzymatic activity, oxidative stress markers, and biomass production of Saccharomyces cerevisiae Thermosacc®, cultivated in corn hydrolysate—a non-synthetic medium that provides a more realistic representation of industrial environments—under aerobic and anaerobic conditions. Antioxidant responses were assessed via glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione S-transferase (GST) activities, while oxidative stress was measured through hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) levels. Yeasts were grown with 0, 200, and 400 mg L−1 Na₂SeO₃. The highest enzymatic activities were observed in AE400 (GPx: 5.35 μmol mg−1, GR: 3.39 μmol mg−1, GST: 0.035 μmol mg−1), indicating enhanced antioxidant defenses under aerobic Se supplementation. However, increased Se concentrations also elevated H₂O₂ and MDA levels—especially in aerobic conditions—likely due to intensified ROS generation. Consequently, biomass production and growth parameters declined, suggesting an energy trade-off in which antioxidant defense is prioritized over cell proliferation. These findings highlight Se’s dual role as both an antioxidant and a pro-oxidant at elevated concentrations. This study advances understanding of yeast redox biology and supports the integration of Se-enriched yeast production into industrial fermentation as a sustainable strategy for generating high-value functional ingredients for food and feed applications.