Enzymatic Hydrolysis, Kinetic Modeling of Hemicellulose Fraction, and Energy Efficiency of Autohydrolysis Pretreatment Using Agave Bagasse

Agave bagasse is a promising and interesting raw material for the development of second-generation biorefineries. However, the intrinsic resistance (recalcitrance) of lignocellulose biomass to enzymatic hydrolysis is a barrier to its effective conversion into fermentable sugars. Therefore, an autohydrolysis process under subcritical conditions is an alternative to provide the fractionation of biomass in terms of biorefinery concept. In this work, agave bagasse as a feedstock was subjected to the autohydrolysis pretreatment at controlled operational conditions (180 degrees C - 50 min), providing fractionation of biomass > 41.71 % glucan content in the pretreated solid phase (cellulose+lignin fraction). Also, a kinetic modeling of hemicellulose fraction (liquid phase after the pretreatment) for the depolymerization has been studied, considering a linear kinetic mechanism. The cellulolytic hydrolysis process improved the glucose concentration by 40.98 g/L at 72 h with a saccharification yield conversion of 82.58%. The energy efficiency (eta) during the autohydrolysis pretreatment was determined (1.039 g(sugars)/MJ). The design and development of this process will allow establishing optimal operating conditions and energy efficiency for the development of biorefineries with an impact on the circular bioeconomy.

Automated summary

Agave bagasse shows potential as raw material for second-generation biorefineries, however, the recalcitrance of lignocellulose biomass hinders its conversion into fermentable sugars. This study explores an alternative autohydrolysis process to fractionate the biomass, with the pretreated solid phase containing more than 41.71% glucan content. A kinetic modeling of hemicellulose fraction depolymerization was also conducted. The cellulolytic hydrolysis process yielded a significant increase in glucose concentration and achieved high saccharification conversion.