Using poly(vinyldodecylimidazolium bromide) for the in‐situ product recovery of n‐butanol
Vincent, Rachel H.
Parent, J. Scott
Daugulis, Andrew J.
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The mitigation of end‐product inhibition during the biosynthesis of n‐butanol is demonstrated for an in‐situ product recovery (ISPR) system employing a poly(ionic liquid) (PIL) absorbent. The thermodynamic affinity of poly(vinyldodecylimidazolium bromide) [P(VC12ImBr)] for n‐butanol, acetone and ethanol versus water was measured at conditions experienced in a typical acetone‐ethanol‐butanol (ABE) fermentation. In addition to providing a high n‐butanol partition coefficient (PC = 6.5) and selectivity (αBuOH/water = 46), P(VC12ImBr) is shown to be biocompatible with Saccharomyces cerevisiae and Clostridium acetobutylicum. Furthermore, the diffusivity of n‐butanol in a hydrated PIL provides absorption rates that support ISPR applications. Using a 5 wt% PIL phase fraction relative to the aqueous phase mass, P(VC12ImBr) improved the volumetric productivity of a batch ABE ISPR process by 31% relative to a control fermentation. The concentration of n‐butanol in the P(VC12ImBr) phase was sufficient to increase the alcohol concentration from 1.5 wt% in the fermentation medium to 25 wt% in the saturated PIL, thereby facilitating downstream n‐butanol recovery.