Fractionation and delignification of empty fruit bunches (EFB) was conducted in a series of two steps under low reaction severity with the aim of minimizing the neutralization of hydrolyzates. In EFB underwent acid fractionation, the glucan content was increased to 62.4%, at which point 86.9% of the hemicellulosic sugar and 20.5% of the lignin were extracted from the raw EFB. Xylose-rich hydrolyzate, indicating a high selectivity of 17.7 could be separated. Through the consecutive delignification of acid-fractionated EFB using sodium hydroxide, solid residue with a high glucan content (70.4%) and low hemicellulosic sugar content (3.7%) could be obtained, which indicated that 95.9% of the hemicellulosic sugar and 67.5% of the lignin were extracted based on raw EFB. The final pretreated solid residue was converted to glucose through enzyme hydrolysis, which resulted in an enzymatic digestibility of 76.9% was achieved. (c) 2013 Elsevier Ltd. All rights reserved.