A fractionation of wheat straw components in a two-step chemical pretreatment is proposed. Hemicelluloses were hydrolysed by dilute sulphuric acid, allowing a substantial recovery of crystalline xylose. Lignin was removed by means of a mild alkaline/oxidative solubilisation procedure, involving no sulphite or chlorine and its derivatives. The use of diluted reagents and relatively low temperatures, was both cheap and environmentally friendly. The pretreated material was nearly pure cellulose, whose enzymic hydrolysis proceeded fast and with high yields, leading to high glucose syrups of remarkable purity. (C) 2002 Elsevier Science Ltd. All rights reserved.