Hydrothermal pretreatment of sugarcane bagasse is a water-based and environment-friendly process that results in almost complete hemicellulose solubilization in oligomeric form as xylooligossacharides (XOs). However, the soluble XOs cannot be utilized by microorganisms such as yeasts, and therefore,...

Hydrothermal pretreatment of sugarcane bagasse is a water-based and environment-friendly process that results in almost complete hemicellulose solubilization in oligomeric form as xylooligossacharides (XOs). However, the soluble XOs cannot be utilized by microorganisms such as yeasts, and therefore, a further break down is necessary to generate pentose (C5) monomers that can be then biotransformed into ethanol or other metabolites. The kinetics of XOs post-hydrolysis with sulfuric, maleic, and oxalic acids (the latter two being dicarboxylic acids) in a sugarcane bagasse hemicellulosic hydrolysate was assessed in a bench-scale reactor (2 L). By means of a 22 full factorial design with center point triplicate, acid mass loading and temperature were varied from 0.5 and 2.0% and from 120 to 150 °C, respectively. An irreversible first-order consecutive reaction model of the hydrolysis of XOs in liquid medium was employed. Based on an Arrhenius-type equation, a kinetic parameter estimation was performed with genetic algorithms and the Runge-Kutta methods. For the three acids, the calculated exponential factors, A 0n (n = 1, 2, and 3), ranged from 1012 to 1015 min−1; the dimensionless parameters, m n (n = 1, 2, and 3), ranged from 0.86 to 1.97; and the activation energies ranged from 89 to 129.8 kJ·mol−1. The model—developed at microscale—correctly described the observed XOs, C5, and furfural post-hydrolysis profiles in bench scale and proved the dicarboxylic acids were more selective towards post-hydrolysis by having slower kinetics than sulfuric acid

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP

2013/05369-2

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