Deep eutectic solvents to obtain xylitol

Romaní A, Morais ES, Soares PO, Freire MG, Freire CSR, Silvestre AJD, Domingues L (2020) Aqueous solutions of deep eutectic systems as reaction media for the saccharification and fermentation of hardwood xylan into xylitol. Bioresource Technology 311, 123524. https://doi.org/10.1016/j.biortech.2020.123524.

Abstract: The aim of this study was to evaluate the effect of aqueous solutions of deep eutectic solvent, Cholinium Chloride:Urea ([Ch]Cl:U) at 50 wt% and 20 wt%, using different molar ratios (1:1, 2:1 and 1:2) on the enzymatic hydrolysis of xylan for xylose production and its subsequent bioconversion into xylitol using a recombinant yeast strain. The lowest xylan conversion into xylose (45%) was obtained using 1:2 [Ch]Cl:U molar ratio. On the other hand, the 1:1 [Ch]Cl:U molar ratio, at 20 wt% in water, improved this conversion, achieving the highest xylose yield (81.4%). The xylitol production was then optimized with [Ch]Cl:U (1:1) at 20 wt% by simultaneous saccharification and fermentation process, attaining 23.67 g/L, corresponding to 66.04% of xylitol yield. This study reveals the possibility of using xylan solubilized in DES aqueous solutions directly for xylitol production, thus assembling a one-step process.

Link to journal article: https://doi.org/10.1016/j.biortech.2020.123524.

Link to open access repository: http://hdl.handle.net/1822/65580.

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