Patent ID: 8617861

Claim:
A method for recovering butanol from a fermentation medium, the method comprising: a) providing a fermentation medium comprising butanol, water, at least one electrolyte at a concentration at least sufficient to increase the butanol partition coefficient relative to that in the presence of the salt concentration of the basal fermentation medium, and a genetically modified microorganism that produces butanol from least one fermentable carbon source; b) contacting the fermentation medium with i) a first water-immiscible organic extractant selected from the group consisting of C 12 to C 22 fatty alcohols, C 12 to C 22 fatty acids, esters of C 12 to C 22 fatty acids, C 12 to C 22 fatty aldehydes, C 12 to C 22 fatty amides, and mixtures thereof, and optionally ii) a second water-immiscible organic extractant selected from the group consisting of C 7 to C 22 fatty alcohols, C 7 to C 22 fatty acids, esters of C 7 to C 22 fatty acids, C 7 to C 22 fatty aldehydes, C 7 to C 22 fatty amides, and mixtures thereof to form a two-phase mixture comprising an aqueous phase and a butanol-containing organic phase; and c) recovering the butanol from the butanol-containing organic phase to produce recovered butanol.