Regular articleExtractive fermentation for enhanced isopropanol and n-butanol production with mixtures of water insoluble aliphatic acids and oleyl alcohol

- Mixtures of aliphatic acids with oleyl alcohol improved IB extractive fermentation.
- A mixture of dodecanoic acid and oleyl alcohol can recover IB at high concentration.
- Liquid-liquid extraction using mixed extractant has potential in IB production.

Liquid-liquid extractions using the mixtures of aliphatic acids and oleyl alcohol as extractants are investigated to improve isopropanol and butanol (IB) production in fed-batch fermentation. Extractive fermentation with a mixture of tetradecanoic acid (30%) and oleyl alcohol improved IB production by 63.41% compared with fermentation without extraction. A mixture of dodecanoic acid (35%) and oleyl alcohol was 24.75% more effective that the tetradecanoic acid system. The IB yield and productivity were 0.53 g/g and 0.35 g/L/h, respectively for the dodecanoic acid system. The accumulated IB in the dodecanoic acid containing extractant reach a relatively high level of 65.92 g/L from four sequential continuous fed-batch fermentation batches. Online extractive fermentation using the mixture of dodecanoic acid and oleyl alcohol as extractant can recover and accumulate IB at high concentration, which will facilitate subsequent IB purification and significantly improve IB production as a future technique reserve.