Detoxification of corn stover hydrolysate using surfactant-based aqueous two phase system

BACKGROUND: Pretreatment methods used to break down lignocellulose structure lead to the generation of compounds that inhibit ethanol fermentation. Hence, removal of these compounds is essential for improved fermentability. The surfactant-based cloud point extraction (CPE) aqueous two phase system is a new method having the potential for separation and recovery of inhibitors. The present work examines the potential of surfactants-based CPE systems as a detoxification method. RESULTS: Surfactants L62D and L62LF achieved more than 90% removal of phenolic compounds and less than 20% removal of acetic acid and HMF from a model system when the surfactant concentration was 1% and 5%. With untreated simulated hydrolysate containing inhibitors the fermentation was inhibited completely. Detoxification of the same hydrolysate with L62D (1% and 5%) and L62LF (1% and 5%) showed complete fermentation with high ethanol productivity (0.61gL^-1h^-1). Similarly, the detoxified corn stover hydrolysate showed delayed fermentation. The productivity increased by 30% after detoxification with 1% of the two surfactants and by 100% with 5% of the surfactants (L62D and L62LF). CONCLUSION: The new surfactant-based detoxification method significantly improved the fermentability of simulated hydrolysate and corn stover hydrolysate.