The bacterial strain Faecalibacterium prausnitzii (DSM No. 17677, DSMZ collection, Braunschweig, Germany) was cultured under anaerobic conditions (anaerobic chamber: N2 = 90%, CO2 = 5% and H2 = 5%) at 37°C, in brain heart infusion broth (BHI, 37g/L, Difco) supplemented with yeast-extract (5g/L, Difco) cellobiose (1mg/mL, Sigma), maltose (1 mg/mL, Sigma) and cysteine (0.5 mg/mL, Sigma), namely the BHIS medium. The strain was defrosted and cultivated at a 10% inoculation in 10 mL BHIS for 24 hours at 37°C, followed by a 1% inoculation in 10mL BHIS for overnight growth (16-18 hours). The experimental cultures were then made at 2% inoculation in 50 mL BHIS medium with or without supplemented sodium-acetate solution (20 mM, Sigma, (10, 11)), namely the BHISA medium, at the time of inoculation.