Multi-response optimization of acid hydrolysis in sugarcane bagasse to obtain high xylose concentration

Sugarcane bagasse is an agro-industrial waste produced from the sugar industry, which is composed of cellulose, hemicellulose, and lignin. It can be used as a raw material to get xylose, which is used to obtain various products of industrial interest, such as bioethanol and xylitol, among others. The objective of this work was to optimize the acid hydrolysis stage of sugarcane bagasse to obtain the maximum of xylose and the minimum of acetic acid concentration. The response surface methodology and the desirability criterion were used, evaluating the concentration of sulfuric acid (H₂SO₄: 1, 2, 3% v/v), the solid-liquid ratio (LSR: 6, 9, 12 ml/g), and reaction time (t: 10, 20, 30 min), as dependent variables and as response variables the maximum of xylose and the minimum of acetic acid concentration. The optimal conditions found by acid hydrolysis were 0.86% v/v of H₂SO₄, 22.7 min of reaction time, and 6.2 of LSR showing values of 20.0 g/L of xylose and 3.05 g/L of acetic acid. These conditions were experimentally validated, obtaining 20.37 ± 0.12 g/L, while the acetic acid concentration was 2.82 ± 0.05 g/L. These results showed that the optimization method used is good, since it was possible to accurately validate the conditions obtained, achieving similar results to those found by the optimization model, and also 75% of removal of hemicellulose was revealed.