The aim of this work is to explore the potentiality of a porous stainless steel (PSS) supported Pd-based membrane reactor (MR) for hydrogen production via bio-ethanol steam reforming reaction (BESR). Bio-ethanol may be produced from fermentation of cheese by-product waste, which contains major impurities like acetic acid and glycerol. In this work, a simulated bio-ethanol mixture is utilized and contains besides ethanol and water also acetic acid and glycerol with 1:13:0.18:0.04 molar ratio, directly supplied to the MR. In the overall experimental campaign, BESR reaction is performed at 400 degrees C and in a reaction pressure range of 8-12 bar (abs.) using both Ni/ZrO2 and Co/Al2O3 commercial catalysts, packed in the annulus of the membrane reactor. The present study illustrates the influence of the reaction pressure and gas-hour-space-velocity on the MR performances in terms of bio-ethanol conversion, hydrogen recovery factor (HRF), hydrogen permeate purity (HPP) and yield of hydrogen. Furthermore, the effect of the by-products such as acetic acid and glycerol on the MR performances is investigated. In Pd/PSS MR, the best result of this work is obtained at 12 bar and 800 h(-1) as GHSV and using the Co-based catalyst with around 94% of bio-ethanol conversion, 40% of hydrogen yield and HRF similar to 40% with a HPP of 95%. (c) 2012 Elsevier B.V. All rights reserved.