ALTERNATIVE XYLITOL EXTRACTION VIA HPLC PURIFICATION FROM FERMENTED BIOMASS

Importance of the Topic

Second-generation biorefineries focus on converting C5-sugar–rich residues into valuable products. Xylitol, a widely used low-calorie sweetener, can be obtained as a by-product of hemicellulose fermentation. Developing efficient purification strategies for xylitol enhances biomass valorization and supports sustainable bioprocessing.

Objectives and Study Overview

This study evaluated polymer‐based Eurokat HPLC columns for the separation and purification of xylitol from a hemicellulose‐like fermentation mash. Key goals were to identify the optimal stationary phase, quantify by‐products, and establish a semi-preparative batch process yielding high‐purity xylitol.

Methodology

The fermentation mash, provided by Vogelbusch Biocommodities, was centrifuged, filtered (0.45 µm) and diluted 1:10. Analytical screening employed three Eurokat columns under aqueous elution:

• Eurokat Na and H (300×8 mm, 10 µm, 0.5–0.6 mL/min, 75 °C or 60 °C)
• Eurokat Ca analytical (300×8 mm, 10 µm, 0.5 mL/min, 75 °C)
• Calibration standards covered xylose, arabinose, glycerol, mannitol and xylitol (0.3–15 mg/mL).

Preparative purification used a semi-preparative Eurokat Ca column (250×16 mm, 25–56 µm, 2.5 mL/min, 75 °C) with overload testing up to 1 500 µL injections.

Used Instrumentation

• Analytical HPLC: KNAUER AZURA P 6.1L HPG pump (10 mL), 3950 autosampler, AZURA DAD 2.1L with LightGuide, AZURA RID 2.1L, AZURA CT 2.1 thermostat, OpenLAB® EZChrom.
• Preparative HPLC: AZURA P 6.1L HPG pump (50 mL), 3950 preparative autosampler, AZURA RID 2.1L detector (EDR mode), AZURA CT 2.1, Foxy R1 fraction collector, OpenLAB® EZChrom.

Main Results and Discussion

Column screening demonstrated superior baseline separation of xylitol on the Eurokat Ca analytical column despite a longer run time (~28 min). Five fermentation components were quantified:

• Xylitol: 80.6 mg/mL
• Glycerol: 21.0 mg/mL
• Arabinose: 8.3 mg/mL
• Xylose: 8.2 mg/mL
• Mannitol: 7.0 mg/mL

Semi-preparative batch purification yielded xylitol with 99 % purity and 95 % recovery. Overload experiments confirmed robust peak shape retention for xylitol up to 1 500 µL injection, with only minor shifts in early eluting components. Alternative columns (Na, H) failed to resolve xylitol effectively.

Benefits and Practical Applications

This HPLC‐based strategy delivers high‐purity, water‐soluble xylitol directly from fermentation by-products, enabling:

• Integration into food and pharmaceutical formulations
• On-site valorization in biorefineries
• Reduction of downstream processing steps

Future Trends and Potential Uses

Scale-up via larger semi-preparative columns or simulated moving bed (SMB) chromatography could further improve productivity and cost efficiency. Continuous processes and integration with upstream fermentation optimization will enhance commercial viability and expand applications in nutraceutical and pharmaceutical industries.

Conclusion

Eurokat Ca emerged as the preferred stationary phase for xylitol separation from hemicellulose‐derived fermentation mash. The developed semi-preparative HPLC protocol achieves 99 % purity and 95 % recovery, presenting a viable route for sustainable xylitol production from biorefinery residues.