Xylose is a hemicellulosic sugar that can be used as a carbon and energy source for the growth of microorganisms. The main use of xylose is its bioconversion to xylitol. Sorghum straw is a raw material for xylose production that has not yet been studied. The objective of this work was to study xylose production by hydrolysis of sorghum straw at 122degreesC, using three concentrations of sulphuric acid (2%, 41% and 6%). Kinetic parameters of mathematical models for predicting the concentration of xylose, glucose, acetic acid and furfural were found and optimal conditions selected. These were 2% H2SO4 at 122degreesC for 71 min, which yielded a solution with 18.17 g xylose/1, 6.73 g glucose/1, 0.9 g furfural/1 and 1.51 g acetic acid/1. (C) 2002 Elsevier Science Ltd. All rights reserved.