Low liquid–solid ratio (LSR) hot water pretreatment of sugarcane bagasse

Abstract

Low liquid-solid ratio (LSR) can be used to obtain high-content xylo-oligosaccharide (XOS) spend liquor by hot water pretreatment. Developing a technology based on low LSR results in more efficient water usage in the system and thus in lower capital and operating costs. Xylans from xylan rich agro-industrial waste are abundant hemicellulosic polymers with enormous potential for industrial applications. Currently, freeze-dried xylo-oligosaccharides are used as bio-based polymers and hydrolysates containing high xylose contents are converted to several chemical products. In this study, sugarcane bagasse was treated with water at low LSRs and mild temperatures in order to assess the effects of varying the pretreatment conditions on the xylo-oligosaccharide and xylose concentrations, and use a central composite experimental design to optimize the process parameters. The pretreatments were performed in the ranges temperature: 143.3-176.7 °C, time: 20-70 min and LSR: 1 : 1 to 11 : 1 (g g −1 ). The maximum concentrations of xylose and xylan were 13.76 and 36.18 g L −1 (equivalent to 48.29 g L −1 of xylan), respectively, which were achieved by treating bagasse at 170 °C for 60 min, with LSR of 3 g g −1 . The amount of xylan removed under these conditions was almost 57%. The soluble xylan consisted mainly of xylo-oligosaccharides (74 wt% of the identified compound in the spent liquor).

Processing of Biomass with Hydrothermal and Supercritical Water

“…A total conversion of the lignin part and the repolymerized compounds is only possible at high temperatures and short-reaction times, or with the addition of oxygen. Similar investigations on conversion of lignocellulosic material are reported in the literature, for example, on the conversion of rice straw [111], corn stover [112], brewery waste [31], and bagasse [113][114][115]. …”

Liquid hot water pretreatment of lignocellulosic biomass for bioethanol production accompanying with high valuable products

“…Xylo-oligosaccharides constituted by 2 to 7 xylose in β-1,4 glycoside bond connection have benefits for human body, such as adjusting proliferative activity Bifidobacteria in gastrointestinal, enhancing immunity, lowering the level of cholesterol in serum, preventing diarrhea and constipation, and so on (Xiao et al, 2012). Yu et al (2015) detected that the composition in LHW-prehydrolyzed liquid of SB consisted of 31% xylo-pentasaccharide, 33% xylo-tetrasaccharide, 4%xylo-trisaccharide, 1% xylobiose, 2% xylose, and 29% other intangible compounds.Therefore, it will be worth to extract xylo-oligosaccharides from LHW-pretreated liquid Vallejos et al (2012). reported that pretreatment liquid containing high-content xylo-oligosaccharides could be obtained in the LHW process at a low liquid-solid ratio.…”

Avaliação Do Pré-Tratamento Alcalino Do Bagaço De Cana-De-Açúcar Com Hidróxido De Cálcio Visando-Se Ao Aumento Da Digestibilidade Enzimática Da Celulose

“…Os resultados estão de acordo a estudos feitos por Benjamin et al (2013), Vallejos et al (2012) e Zhao et al (2007), nos quais reportou-se que o bagaço de cana-de-açúcar apresenta uma composição variável nas frações de celulose (32,6-45,0%), hemicelulose (23,6-35,0%), lignina (14,4-30%), extrativos (3,1-12,4%) e cinzas (0,6-3,4%). Os resultados da composição de bagaço de cana-de-açúcar pré-tratado em meio alcalino empregando Ca(OH) 2 , são mostrados na Tabela 1.…”