Aiming at the effect of inhibitors on yeast ethanol fermentation during the fuel ethanol biorefinery process

a new green detoxification technology-ionic liquid extraction was developed for detoxification of the prehydrolyzate obtained from washed acid-catalyzed steam-exploded corn stover (ASC). The extractive performances of two kinds of imidazolium-based ionic liquids (alkylimidazolium hexafluorophosphate [Cnmim][PF6](n = 4

6

8) and alkylimidazolium tetrafluoroborate [Cnmim][BF4](n = 6

8)) for the ASC prehydrolyzate were investigated and compared. The results indicated that the extraction efficiency of the inhibitors decreased with the increase of alkyl chain length on the cation of ionic liquids. Ionic liquid with PF6- anion had much higher extraction efficiency for the inhibitors than those with PF6-anion because of the stronger effective charge in BF4-. Compared to the extraction efficiency of sugars and inhibitors

[C8mim][BF4] was selected as the extractant for detoxification of the ASC prehydrolyzate. Its detoxification results indicated that 85.13% of 5-hydroxymethylfurfural

53.22% of formic acid

47.53% of acetic acid and 65.05% of total phenols could be removed

while the loss of sugars was less than 6%.