Kinetic Modeling of the Autohydrolysis of Lignocellulosic Biomass for the Production of Hemicellulose-Derived Oligosaccharides

Abstract

Xylose-based oligosaccharides produced from xylan-rich hemicelluloses (xylo-oligomers) are carbohydrates with potential food and pharmaceutical uses. Autohydrolysis of lignocellulosic biomass is an efficient way to produce xylo-oligomers in a reasonable yield and a wide variety of compositions (anhydroarabinose/anhydroxylose and acetyl/anhydroxylose mass ratios). In this work, we develop a kinetic model for the autohydrolysis of xylan in lignocellulosic biomass that describes the yields of the different reaction products and explains the changes in the chemical composition of the xylo-oligomers due to reaction temperature and time. This model assumes that xylan is made up of three monomers (xylose, arabinose, and acetic acid) and that there are two xylan fractions with different compositions and reactivities toward hydrolysis. Both fractions are hydrolyzed to xylo-oligomers, which are hydrolyzed to xylose, arabinose, and acetic acid. Finally, monosaccharides dehydrate to furfural and degradation products. The model is validated with experimental data obtained for the autohydrolysis of corncobs in a batch reactor system at temperatures from 150 to 190 °C. The amount and composition of each xylan fraction, as well as the activation energies and frequency factors for all the reactions, are calculated from the experimental data. This model provides a satisfactory interpretation of the experimental data.

Extraction of arabinoxylans from wheat bran using hydrothermal processes assisted by heterogeneous catalysts

“…below 100 ºC) is not able to break the cross-links between the WUAXs and the wall matrix (Izydorczyk & Biliaderis, 2007). In order to improve the AXs extraction yield from different biomass, several techniques, such as hydrothermal treatments (Bobleter, 1994;Buranov & Mazza, 2010;Carvalheiro, Garrote, Parajó, Pereira, & Gírio, 2005;Dien et al, 2006;Garrote, Domínguez, & Parajó, 1999;Garrote, Domínguez, & Parajó, 2001;Garrote, Domínguez, & Parajó, 2002;Kim, Hendrickson, Mosier, & Ladisch, 2009;Lavarack, Griffin, & Rodman, 2000;Li, Converse, & Wyman, 2003;Maes & Delcour, 2002;Mok & Antal, 1992;Nabarlatz, Farriol, & Montané, 2004;Negahdar, Delidovich, & Palkovits, 2016;Reisinger et al, 2013;Shen & Wyman, 2011;Tekin et al, 2014), chemical-solvent extractions (Adams et al, 1955;Aguedo, Fougnies, Dermience, & Richel, 2014;Bataillon, Mathaly, Nunes Cardinali, & Duchiron, 1998;Buranov & Mazza, 2010;Choteborská et al, 2004;Doner, Chau, Fishman, & Hicks, 1998;Höije, Gröndahl, TØmmeraas, & Gatenholm, 2005;Hollmann & Lindhauer, 2005;Kim, Kreke, & Ladisch, 2013;Kusema et al, 2011;Lavarack, Griffin, & Rodman, 2002;Maes & Delcour, 2002;Shen & Wyman, 2011;Swennen, Courtin, Lindemans, & Delcour, 2006;Xu et al, 2006;Yao, Nie, Yuan, Wang, & Qin, 2015;…”

“…Hydrothermal treatments are performed in water under relatively high experimental conditions (150-230 ºC) (Garrote et al, 1999). These treatments are green processes and the yields achieved with them are relatively high (58-71%) (Dien et al, 2006;Garrote et al, 2001;Reisinger et al, 2013;Nabarlatz et al, 2004). Chemical methods using bases or acids are not environmentally-friendly and the separation process at the end of the extraction raises sharply the operating costs.…”

Toward Complete Utilization of Miscanthus in a Hot-Water Extraction-Based Biorefinery

“…Removal of xylan ranging between~57% (pilot scale) and 66% (M/K scale) was lower than that reported for hardwoods [15,16]. The lower xylan hydrolyzability may be attributed to relatively low contents of acetyl and arabinose groups [42] and to developed cross-linked structure characteristically present in miscanthus cell walls (diferulate bridges between xylans and ferulate bridges between xylan and lignin [8,43]. Taking into account a reduced xylan removal and higher extraction yields, it seems that HWE is less selective in the removal of xylans from miscanthus than from hardwoods.…”

Hot Water Pretreatment of Boreal Aspen Woodchips in a Pilot Scale Digester

“…There are models describing hot water extraction as a homogeneous system with pseudo-first-order reactions and the extracted xylan having two different reactivities [5,[17][18][19]. Nabarlatz et al proposed a modified pseudo-first-order model that xylan is composed of xylose, arabinose, and acetic acid [20,21]. Other models tend to ignore the possible biphasic nature of xylan and propose more general linear sequence first-order kinetic model [22,23].…”