Growth Conditions for Bacterial Strains

Bacterial strains used are listed in Table 1. E. coli was grown aerobically at 30 °C or 37 °C in Luria-Bertani (LB) broth or agar supplemented with 25 µg/ml chloramphenicol (LB_Cm25) or 100 µg/ml kanamycin (LB_Km100), respectively. C. pasteurianum was routinely grown at 37 °C in an anaerobic workstation (Don Whitley, Yorkshire, UK) in 2x YTG broth (16 g/l tryptone, 10 g/l yeast extract, 5 g/l NaCl, 5 g/l glucose, pH 6.2) or on RCM agar (Oxoid Ltd) supplemented with 15 µg/ml thiamphenicol (2x YTG_Tm15, RCM_Tm15), 20 µg/ml erythromycin (2x YTG_Em20, RCM_Em20) or 40 µg/ml uracil (2x YTG_Ura40, RCM_Ura40), if required. Selections using 5-fluoroorotic acid (FOA, 600 µg/ml; Sigma-Aldrich, Dorset, UK) and uracil (5 µg/ml) were carried out in modified clostridial basal medium containing 0.5% (w/v) CaCO₃ and 5% (w/v) glucose (CBM-S) (Steiner et al., 2012 (link)) or on standard clostridial basal medium (CBM) agar (O'Brien and Morris, 1971 ). All solidified media contained 1.5% [w/v] agar. Solvent/ acid profiling was undertaken in CGM (Sandoval et al., 2015 (link)), Biebl medium (Biebl, 2001 ) or 2x YT media supplemented with 60 g/l glycerol or glucose. Biebl medium was additionally supplemented with 1 g/l yeast extract for glycerol fermentations Table 2.