In this work, laccase enzymes were evaluated to detoxify the whole slurry from steam-exploded wheat straw. For it, two different strategies, laccase treatment before or after enzymatic hydrolysis, were employed. The detoxification efficiency was analyzed on enzymatic hydrolysis and fermentation levels by the thermotolerant yeast Kluyveromyces marxianus. Laccases reduced phenolic compounds without affecting weak acids and furan derivates. A lower glucose recovery was observed when laccase treatments were carried out before enzymatic hydrolysis, phenomenon that was not showed after enzymatic hydrolysis. In contrast, both laccase treatment strategies enhanced ethanol concentrations, reducing significantly the lag phase of the yeast and allowing substrate loading increments of saccharification and fermentation broths. (C) 2011 Elsevier Ltd. All rights reserved.