Production and Fractionation of Xylose Oligomers from Switchgrass Hemicelluloses Using Centrifugal Partition Chromatography

by Bunnell, Kris; Lau, Ching-Shuan; Lay, Jackson O., Jr.; Gidden, Jennifer; Carrier, Danielle Julie

Xylose oligomers are of interest to many fields of study and are intermediate reaction products of the hydrolysis of hemicelluloses. Protocols to generate xylose oligomers are reported, but these methods lead to the production of a pool of nonfractionated xylose oligomers with a wide range in degree of polymerization (DP). This work used switchgrass hemicelluloses as feedstock for production of purified xylose oligomers. Switchgrass hemicelluloses were autohydrolyzed at 160 degrees C. Yields of xylobiose, xylotriose, xylotetraose, xylopentose, and xylohexose were 24, 34, 23, 19, and 38mg, respectively, per g of hemicelluloses. The crude xylose oligomer mixture was fractionated using centrifugal partition chromatography (CPC) with a butanol:methanol:water (5:1:4, V:V:V) solvent system. Xylose oligomers with a DP from two to six were successfully purified. Purities obtained by CPC separation, as calculated by mass of a given oligomer divided by the total mass of detected oligomers and degradation products and then reported on a percent basis, were 75 +/- 7%, 89 +/- 1, 87%+/- 2, 77 +/- 6%, and 69 +/- 12% for xylobiose, xylotriose, xylotetraose, xylopentose, and xylohexose, respectively. This work illustrates that a CPC-based process could be used to fractionate switchgrass xylose oligomers reference standards, which are currently not commercially available.

Journal of Liquid Chromatography and Related Technologies
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1520-572X; 1082-6076