Production of Fermentable Sugars and Hydrogen-Rich Gas from Agave tequilana Biomass

Abstract

The Mexican tequila industry annually processes approximately 1 × 106Agave tequilana plants, generating approximately 1.78 × 108 kg of bagasse per year. This biomass is considered an attractive alternative to fossil fuels as an energy source and to produce biofuels and/or chemical products because it is produced and used without adversely affecting the environment. The first aim of the present work was to determine the effect of temperature, the concentration of H2SO4, and reaction time on the hydrolysis of agave bagasse to maximize the fermentable sugars using a steam explosion. This step process generated 71.11 g/L of reducible sugars in the supernatant (59.29 % glucose, 29.05 % xylose, and 11.66 % fructose) and unconverted organic matter of enzymatic hydrolysis bagasse (35.4 % α-cellulose, 7.33 % hemicellulose, 49.91 % lignin, and 7.31 % ashes). A mathematical surface response analysis of the hydrolysis was used for process optimization. The second aim involves the study of the thermodynamics of the reforming of unconverted organic matter from enzymatic hydrolysis of Agave tequilana bagasse (ATB) evaluated by the Gibbs free energy minimization method for hydrogen production. The effect of the parameters on the system performance measures, such as reaction temperature (T), Water/Biomass ratio (WBR), and pressure (P), were also investigated. The maximum H2 production obtained was 23.2 mol of H2/271.5 g ATB with a WBR ≥ 11 and a temperature of 740 °C. These findings indicate that the temperature and WBR are essential factors in the production of H2, which was reflected in the efficiency of the process.