Chemical and structural characterization of alkaline‐extractable hemicelluloses from various eucalyptus species

Abstract

Eucalyptus species are currently one of the main feedstock for pulping and papermaking industry in China. In the present study, alkali-extractable hemicelluloses were isolated from different eucalyptus species (Eucalyptus camaldulensis, E. urophylla 3 grandis, and E. urophylla 3 E. tereticornis) at mild conditions prior to pulping. Structural characterization of these hemicellulosic polymers based on monosaccharide, molecular weight, Fourier transform infrared, 1 H, 13 C, and two-dimensional heteronuclear single quantum coherence nuclear magnetic resonance analysis revealed that these alkali-extractable polysaccharides shared the common structure composed of the (1!4)-linked-b-D-xylopyranosyl backbone with 4-O-methyl-a-D-glucuronic acid attached to O-2 of the xylose residues. The potential structures of the alkali-extractable hemicelluloses were proposed based on the comprehensive analysis. The well-characterized structures of these hemicelluloses could enlarge the industrial application of these hemicelluloses from the Eucalyptus species in a biorefinery process.

Selective hydrolysis of hemicellulose from wheat straw by a nanoscale solid acid catalyst

“…As a main component of lignocelluloses, hemicellulose might be a promising material for industrial utilization if it could be converted into sugars efficiently (Aristidou & Penttila, 2000;Lange, 2007;So & Brown, 1999). Hemicellulose is generally made up of the C 5 and C 6 sugars (particularly xylose, arabinose, mannose, and glucose) (Anderson, Peterson, Akin, & Morrison, 2005;Wang, Yuan, Ji, & Li, 2013;Wei, Li, Chang, & Wang, 2013). Derivatives of these sugars have been reported as important materials for industrial application (Krogell et al, 2013;Zhou et al, 2013).…”

Materiais lignocelulósicos como matéria-prima para a obtenção de biomoléculas de valor comercial

“…Os agentes alcalinos mais utilizados são: hidróxido de sódio (NaOH), hidróxido de potássio (KOH), hidróxido de cálcio (Ca(OH) 2 ) e amônia. Destes, o mais estudado é o NaOH [62][63][64][65] ; entretanto, o Ca(OH) 2 tem se mostrado efetivo como agente de pré-tratamento e é mais barato que o NaOH 66 . A amônia também tem sido testada para vários resíduos, sendo altamente seletiva na remoção da lignina e abertura do resíduo lignocelulósico, com a vantagem de ser facilmente recuperada devido à sua alta volatilidade 67 .…”

Novel insight in carbohydrate degradation during alkaline treatment

“…Pakkanen et al (2013) investigated the dependence of the carbohydrate degradation products on the cooking parameters during kraft pulping. Studies by Longue et al (2013) and Wei et al (2013) considered the extraction of hemicelluloses from eucalyptus wood through alkaline treatment. Van Heiningen and Ji (2012) and Jafari et al (2014) inspected the combined effect of kraft pulping followed by oxygen delignification on the carbohydrate yield.…”