Screening and identification of extractive fermentation solvents using a database

The ethanol fermentation has been studied as a model system for end product inhibition and extractive fermentation. Examination has been done on the basis of theoretical considerations, as well as experimental evaluation. For the latter case, a database has been developed in order to screen more than 1,500 solvents for their suitability as extractants in the system solvent‐ethanol‐water. Based on this screening, 62 solvents have been tested with yeast cultures to determine experimentally such important parameters as biocompatibility, distribution coefficients and phase stability. Fifteen of these solvents have proven to be completely biocompatible, while 26 were completely toxic, the remaining solvents showing different degrees of inhibition. In this paper, the theoretical and experimental procedures involved in the systematic screening of extractive fermentation solvents will be outlined. Also, some heuristic criteria will be presented that allow for an evaluation of solvent biocompatibility a priori.