Simultaneous saccharification and fermentation (SSF) process for ethanol production from various lignocellulosic woody (poplar and eucalyptus) and herbaceous (Sorghum sp. bagasse, wheat straw and Brassica carinata residue) materials has been assayed using the thermotolerant yeast strain Kluyveromyces marxianus CECT 10875. Biomass samples were previously treated in a steam explosion pilot plant to provide pretreated biomass with increased cellulose content relative to untreated materials and to enhance cellulase accessibility. SSF experiments were performed in laboratory conditions at 42 degreesC, 10% (w/v) substrate concentration and 15 FPU/g substrate of commercial cellulase. The results indicate that it is possible to reach SSF yields in the range of 50-72% of the maximum theoretical SSF yield, based on the glucose available in pretreated materials, in 72-82 h. Maximum ethanol contents from 16 to 19 g/l were obtained in fermentation media, depending on the material tested. (C) 2003 Elsevier Ltd. All rights reserved.