2025 AIChE Annual Meeting

Ion-Exchange Separation of Xylitol

Ion-exchange chromatography (IEC) is a downstream processing method of separation which can be used as a means to separate fermentation hydrolysate containing compounds of varying charge. This work seeks to identify an optimized method of IEC for the separation of xylitol from hydrolysate post-fermentation of xylose using Candida tropicalis yeast. IEC separation of xylose, xylitol, and remaining compounds was performed based on the characteristic differences in charge. IEC was performed using a commercially available Amberlite IRC-748 cationic ion-exchange resin packed in a glass column with a height of 31 cm and diameter of 2 cm. Glass wool was placed on the bottom interior surface (3 - 5 cm) and and was placed on the top interior surface (2 cm). The column was conditioned using distilled deionized water. A 30% ethanol solution by volume was used to disinfect the column. Three water wash cycles were performed using distilled deionized water. Initial sample eluent was not expected to contain xylitol due to affinity towards resin. Addition of water elutes the xylitol from the resin bed, because of the increased affinity towards the water.. High-performance liquid chromatography (HPLC) and pH analysis was performed on ion-exchange elutions from time retention time trials of 1, 3, and 10 minutes to quantify xylitol concentrations. pH values were consistent across water wash cycles and pH control methods. Xylitol was not detected, or detected in minimal amounts in the initial eluent. The second water wash cycle detected the greatest mass percentage of xylitol. The third water wash cycle detected the lowest mass percentage of xylitol. These findings indicate a path forward for separating and recovering xylitol from fermentation hydrolysate.