The performance of two lignocellulosic biomasses was studied in high-pressure carbon dioxide/ water pre-treatment. Sugarcane bagasse and elephant grass were used to produce C-5-sugars from hemicellulose and, simultaneously, to promote cellulose digestibility for enzymatic saccharification. Different pretreatment conditions, with combined severity factor ranging from -1.17 to -0.04, were evaluated and maximal total xylan to xylose yields of 59.2 wt.% (34.4 wt.% xylooligomers) and 46.4 wt.% (34.9 wt.% xylooligomers) were attained for sugarcane bagasse and elephant grass, respectively. Furthermore, pre-treated biomasses were highly digestible, with glucan to glucose yields of 77.2 mol% and 72.4 mol % for sugarcane bagasse and elephant grass, respectively. High-pressure carbon dioxide/ water pretreatment provides high total C-5-sugars and glucose recovery from both lignocellulosic biomasses; however it is highly influenced by composition and intrinsic features of each biomass. The obtained results confirm this approach as an effective and greener alternative to conventional pre-treatment processes. (C) 2016 Elsevier Ltd. All rights reserved.