Hydrolysis of sugarcane bagasse in subcritical water

•Subcritical water hydrolysis of sugarcane bagasse was conducted at 213–290 °C.•Maximum total reducing sugars recovered was 23%.•Approximately 60% of the sugars recovered were in the oligomeric form.•It seems a promising technology for the recovery of sugars from sugarcane bagasse.

In this work, a subcritical water process was used for the hydrolysis of sugarcane bagasse with the aim of producing fermentable sugars. Hydrolysis kinetics was determined using a semi-batch unit equipped with a 50 mL reactor. Different sample loads (2 and 11 g), flow-rates (11, 22, 33, 44 and 55 mL/min) and temperatures (213, 251 and 290 °C) were evaluated, while maintaining constant pressure (20 MPa). The liquefaction degree of the sugarcane bagasse was not affected by water flow rate and increased with temperature; the maximum liquefaction degree was 95% for hydrolysis at 251 °C and 33 mL/min. The total reducing sugars recovered increased with flow rate up to 23%. The hydrolysis process was completed faster at higher temperatures, requiring 16 min. Maximum monosaccharides + cellobiose + cellotriose yield was 5.6% at 213 °C and 33 mL/min. Approximately 60% of the sugars recovered were in the oligomeric form.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide