The antioxidant defence of Dekkera bruxellensis against hydrogen peroxide and its relationship to nitrate metabolism.

This article focuses on the oxidative stress response mechanisms of the yeast Dekkera bruxellensis, particularly its sensitivity to hydrogen peroxide (H₂O₂) compared to Saccharomyces cerevisiae. The study found that D. bruxellensis employs a defense system primarily involving glutathione peroxidase (Gpx) and sulfhydryl-containing proteins (PT), which is more active under respiratory metabolism induced by non-glucose carbon sources like galactose, citrate, or glycerol. However, when nitrate (NO₃) is used as the nitrogen source, this antioxidant defense is suppressed, increasing the yeast's sensitivity to H₂O₂ despite elevated expression of some oxidative stress genes. These findings have implications for the industrial use of D. bruxellensis in fermentation processes involving substrates containing oxidants and highlight the complex interplay between carbon and nitrogen metabolism in regulating oxidative stress tolerance.