For the purpose of hydrolysing hemicelluloses to oligomers and monomers, Sesbania grandiflora samples were subjected to isothermal autohydrolysis in the temperatures ranging from 145 degrees C to 190 degrees C, using a solid to liquid ratio of 8 and reaction times up to 7.5 h. Kinetic models based on sequential pseudo-homogeneous first order Kinetics with Arrhenius type temperature dependence were employed for describing the time course of the main hemicelluloses compounds and their degradation products. The hydrothermal treatment results show that Sesbania grandiflora can be employed as an alternative raw material for the production of XOS leading to high concentrations of XOS (14.1 g/L in the experiment carried out at 190 degrees C and 0.1 h) and xylan to XOS conversion (62.6% in the experiment carried out at 190 degrees C and 6 min). The model proposed provides a satisfactory interpretation of the experimental data obtained in the hydrothermal treatments of this study. (C) 2009 Elsevier Ltd. All rights reserved