Fig. 2

Fermentation productivity during addition of methyl viologen to chemostat culture. Specific fermentation products (converted to reflect the amount of carbon in the products; mol C-equivalents/L/OD₆₀₀) are reported in equivalent carbon mole basis (e.g., 1 mol ethanol = 2 mol C-equivalent). Productivity in carbon moles is normalized to OD₆₀₀ to account for changing cell yields observed across the time culture was exposed to methyl viologen. CO₂ productivity is estimated by assuming one mole of CO₂ is produced for each mole of ethanol and each mole of acetate produced. Green arrow indicates when methyl viologen exposure began and purple arrow indicates time when methyl viologen flushing from the reactor began