Solvent screening methodology for in situ ABE extractive fermentation.

Abstract : A systematic solvent screening methodology for the in situ liquid extraction of products from Acetone-Butanol-Ethanol fermentation was developed in this study. on the basis of theoretical considerations, sixteen compounds from different chemical families were selected and experimentally evaluated for their extraction capabilities in a real ABE fermentation broth system. The best potential solvents were also tested for their biocompatibility towards Clostridium acetobutylicum. Differences in substrate consumption and total butanol production referred to solvent-free fermentations were quantified for each solvent. It was observed that a) the excess of glucose consumption does not lead systematically to the same amount of overproduction of butanol with the biocompatible solvents and b) product yield was enhanced in the presence of solvents having higher affinity for butanol and butyric acid. Applying this methodology, it was found that the solvent that presented the best extracting characteristics and maintained biocompatibility with C.acetobutylicum was the Guerbet alcohol 2-butyl-1-octanol.