Intracellular ROS accumulation. Percentage of cells that accumulate ROS during fermentations at 30°C (left panels) and 41°C (right panels) under different concentrations of inlet oxygen: 20.95% (a), 11.00% (b), and 1.75% (c). For each condition, an example of positive control (i.e.: cells treated with 6 mM hydrogen peroxide) is reported. The results shown are average values of three replicates where the deviation from the mean value was always less than 5%.