At a substrate concentration of 1x(wlv) an ethanol yield of 80(w/w theoretical) was achieved. However at a substrate concentration of ethanol yield was lowered to 18.8x(wlw, theoretical). Yields were considerably mproved by increasing liquor. These the yeast titre in the inoculum or preconditioning the yeast on steam exploded tration of approaches enhanced the ethanol yield up to(wlw, theoretical) a substrate concen 20% (wlv) by metabolising at fermentation inhibitors. c 2015 The Authors. Published by Elsevier Ltd. This is an open accessarticle underthe cc NDlicense