Development and characterization of butanol-resistant strain of Clostridium acetobutylicum in molasses medium

The production of acetone-butanol-ethanol solvents from cane molasses by locally isolated culture of Clostridium acetobutylicum was limited by butanol toxicity (1.6 mol/L). The butanol tolerance of the isolated culture was increased up to 4.8 mol/L by a serial enrichment method. The butanol-resistant strain had greater efficiency for the conversion of saccharides to mixed solvents and produced 52 % more butanol at the expense of acetone and ethanol than the original strain. Moreover, the fermentation profile of parent and butanol-resistant strains in anaerobic fermentation of cane molasses demonstrated the superiority of the latter in terms of growth rate, time of onset of butanol production, sugar utilization, final butanol concentration and other parameters.