The kinetic behaviour of the yeast Candida guilliermondii FTI 20037 was evaluated on a bench bioreactor using rice straw hydrolysate as a substrate. The maximum xylitol concentration (45.4 g l(-1)) was attained after 45 h of fermentation, which corresponded to a xylitol volumetric productivity of 1.01 g l(-1) h(-1). This value was improved in about 90% when compared to the results attained with aerated flasks (0.54 g l(-1) h(-1)). The kinetic results obtained in the present work reinforce the idea that rice straw hydrolysate constitutes an effective xylose source for xylitol production. (c) 2005 Elsevier Ltd. All rights reserved.