Biomass-based fuels provide a promising route to avoid environmental issues and the global political instability that arise from depending on petroleum. Currently, biomass conversion remains costly primarily because of the intrinsic recalcitrance of biomass. Improved manipulation of lignin can be a promising path to solving this problem. Through evaluation via fiber analysis, enzymatic hydrolysis, ethanol fermentation, thermogravimetric analysis, and pyrolysis-gas chromatography/mass spectrometry, we show here that the modulation of lignin deposition/composition of barley straw produced phenotypically normal plants that reduced thermo-chemical, enzymatic, and microbial recalcitrance. This study reveal mutation of barley for low phytic acid content in the grain decreases lignin content modestly, preferentially decreases the guaiacyl (G) lignin conterpart, moreover, enhances the ethanol yield by up to 21.1% using conventional biomass fermentation processes after diluted acid pretreatment. Therefore, this apparent reduction in the recalcitrance of mutant has the potential to significantly lower the processing costs for biomass-derived fuels and chemicals, and be valuable for developing improved cultivars of biofuel crops. (C) 2012 Elsevier Ltd. All rights reserved.