Comparison of Two Adsorbents for Sugar Recovery from Biomass Hydrolyzate

Two polymeric adsorbents, Dowex99 and poly(4-vinyl pyridine) (PVP), have been studied for the recovery of sugars from a corn-stover hydrolyzate. The major components of the hydrolyzate are five sugars, glucose, xylose, mannose, arabinose, and galactose, and four impurities, sulfuric acid, acetic acid, hydroxymethyl furfural (HMF), and furfural. In elution chromatography in a column packed with Dowex99, the five sugars are the "center-cut", whereas sulfuric acid elutes earlier and the other three impurities elute later than the sugars. For a column packed with PVP, the sugars elute earlier than all the impurities. The intrinsic adsorption and mass-transfer parameters of the sugars and the major impurities were obtained from elution and frontal chromatography tests of single components. The experimental elution chromatograms of the hydrolyzate are in close agreement with the simulations based on a detailed rate model and the single-component intrinsic parameters. The results indicate that other unidentified impurities in the hydrolyzate do not affect the adsorption of the identified components. The hydrolyzate sugars recovered from the batch elution chromatography processes were fermented with genetically engineered yeast. The fermentation results show that the hydrolyzate sugars recovered from the PVP columns have the highest fermentability, compared with those for an overlimed hydrolyzate and the sugars recovered from the Dowex99 columns.