Scale-up and evaluation of hydrothermal pretreatment in isothermal and non-isothermal regimen for bioethanol production using agave bagasse

Abstract

The production of tequila in Mexico generates a large amount of agave bagasse per year. However, this biomass can be considered as a potential source for biofuel production. In this study, it is described how the hydrothermal pretreatment was scaled in a bench scale, considering the severity index as a strategy. The best condition was at 180 °C in isothermal regime for 20 min with 65.87% of cellulose content and high concentration of xylooligosaccharides (15.31 g/L). This condition was scaled up (using severity factor: [logR₀] = 4.11), in order to obtain a rich pretreated solid in cellulose to perform the enzymatic hydrolysis, obtaining saccharification yields of 98.5 and 99.5% at high-solids loading (10 and 15%, respectively). The pre-saccharification and fermentation strategy was used in the bioethanol production at 10 and 15% of total pretreated solids, obtaining 38.39 and 55.02 g/L of ethanol concentration, corresponding to 90.84% and 87.56% of ethanol yield, respectively.

Keywords: Agave; Autohydrolysis; Biorefinery; Enzymatic hydrolysis; Lignocellulosic biomass.