Fig. 2

Cells growth (a) and butanol production (b) of C. beijerinckii 3304::int. Cells were grown in screw-capped bottles in fermentation medium containing 30 g/L glucose and 0.5 g/L of six model phenolic compounds. 3304: strain C. beijerinckii 3304::int; 3304(Ca): C. beijerinckii 3304::int with 3 g/L of CaCO3 supplemented