Actinobacillus succinigeneis 130z is quite flexible in its ability to efficiently produce succinic acid through fermentation of different carbon sources commonly found in hydrolysate. But this strain is very sensitive to some phenolic compounds present in biomass hydrolysate, resulting in dramatically reduced fermentation efficiency and succinic acid yield. This inhibition is more serious in concentrated hydrolysate where both sugars and inhibitors may be 4 to 10 times higher in concentration than in the original hydrolysate. So the detoxification process is required before the fermentation start.
Current methods for removing the phenolic compounds include adsorption on activated carbon or ion-exchange resins. In addition to being expensive, there methods are non-selective and less efficient. Therefore, we propose to use two-phase liquid extraction instead. The phenolic compounds are removed from the aqueous solution and transported to the low-toxic and immiscible organic solvent (e.g. hexane, 2-octanol) containing an extractant, tri-n-octyl phosphine oxide (TOPO). The extracted phenolic compounds can be stripped from the organic into a higher pH aqueous receiving phase to regenerate the organic phase. These three methods, activated carbon, ion-exchange resins and two-phase liquid extraction, will be compared for ionic liquid hydrolysates, with and without concentration, with respect to sugar loss and phenolic compounds removal efficiency to evaluate performance.