Strain comparison and medium preparation for the acetone-butanol-ethanol (ABE) fermentation process using a substrate of potato

Several strains of solvent-producing clostridia were investigated for their ability to produce solvents from unsupplemented potato and from potato that had been pre-hydrolysed with amylolytic enzymes. Most of the strains were strongly solventogenic and prior treatment with the enzymes gave no improvement in this property. C. acetobutylicum DSM 1731 showed a reactor productivity of 0•24 g/l/h on unhydrolysed potato, and was the most productive strain tested. In contrast, C. acetobutylicum ATCC 824 was only weakly solventogenic unless the potato was pre-hydrolysed using amylolytic enzymes.