Fig 5.

Biomass (A) and total ABE (B) profiles of C. beijerinckii fermentation in EDTA-supplemented P2 medium following the addition of solutions X (0.5 g/liter Ca²⁺), Y (0.23 g/liter total Fe²⁺, Mn²⁺, and Mg²⁺ at a ratio of 2:3:40), and Z (0.5 g/liter Ca²⁺ plus 0.23 g/liter total Fe²⁺, Mn²⁺, and Mg²⁺ at a ratio of 2:3:40). Arrows indicate the addition of solutions X, Y, and Z at 4 h of fermentation.