Sustainable Production of Xylitol (ECC Session)

Xylitol has been identified by the U.S Department of Energy as a target molecule for sustainable production from biomass due to its potential uses in the pharmaceutical and food industry, as well as a starting material for the production of valuable polyols. Current methods of xylitol production are thermochemically intensive as they require high pressures and high temperatures. Additionally, the final hydrogenation step in xylitol synthesis involves expensive metal catalysts. These costly methods of production contribute to a high market price of xylitol and have many environmental impacts. The objective of this work is to explore a biological pathway for the production of xylitol via fermentation that provides a greener alternative and can contribute to a lower xylitol market price. In this research, xylose was fermented to xylitol using C. Tropicalis with and without pH controls. During the fermentation process, periodic aliquots of the fermentation hydrolysate were taken to analyze the cell growth using OD600, track pH measurements, and to be stored for later HPLC analysis. After fermentation, the fermentation hydrolysate was passed through a commercially available cationic exchange resin, Amberlite IRC-748 to separate the xylitol from other fermentation byproducts. The samples were then concentrated on a hot plate to produce a saturated solution and subsequently induce crystallization of the xylitol in solution. Characterization of the separated, crystallized xylitol was conducted using FT-IR, XRD, and DSC. Techno-economic analysis and a life cycle assessment of a xylitol biorefinery based on this experimental work were then simulated using BioSTEAM.