Study of charcoal adsorption for improving the production of Xylitol from wood hydrolysates

Xylose-containing solutions, obtained from acid prehydrolysis of Eucalyptus wood, were treated with powdered charcoal in order to remove lignin-derived compounds that limit the potential of hydrolysates for making fermentation media. Both the kinetics and equilibrium of adsorption were modelled using equations reported in literature. Charcoal-pretreated hydrolysates were supplemented with nutrients and used for producing xylitol with the yeast Debaryomyces hansenii NRRL Y-7426. The susceptibility to fermentation of culture media made with this procedure was compared with those corresponding to media made from untreated wood hydrolysates or standard xylose solutions. The removal of lignin-derived compounds from hydrolysates was closely related with the efficiency of fermentation.