Carbohydrates obtained from hydrothermal treatment of sugarcane bagasse

VALLEJOS, M.E.; FELISSIA, F.E.; KRUYENISKI, J.; AREA, M.C.

Sao Paulo

Congreso; 44° Congresso e Exposição Internacional de Celulose e Papel; 2011

ABTCP

Bagasse is a lignocellulosic agro-industrial waste, which is usually burned in the sugar and bio-ethanol mills to produce heat and electricity. Since cellulose and hemicelluloses are its main components, these substances could be used, for example, as intermediates in the production of bioethanol from glucose and xylitol from xylose. The aim of this work was to study the hydrothermal pretreatment of sugarcane bagasse. The variation of the main products generated was evaluated, and the best time to obtain a high concentration of pentosans and low concentrations of degradation products in the spent liquor was established. Sugarcane bagasse was hydrothermally treated under isothermal conditions at 180°C, using a liquid to solid ratio of 14:1. Glucans, pentosans, xylose, glucose, arabinose, acetic acid, formic acid, HMF and furfural were first identified in the spent liquor. The extraction of pentonsans from the solid, and the oligomers, pentoses, and furfural, was studied by a kinetic model. A first order kinetics for the extraction of pentosans from the solid material was tried. The fractionation by hydrothermal treatment has proven to be effective for hemicelluloses removal. Most of the glucan was retained in the solid and a partial delignification was achieved (9.8% and 36.3% of initial lignin at 20 y 240 min of treatment, respectively). Pentosans were fully removed after 180 min, producing pentoses (arabinose and xylose) and furfural. The maximum concentration of pentosans in the residual liquor was achieved at 20 min of treatment (17.76% o.d.b., about 70% of initial amount), with the low furfural content (0.5% o.d.b.).