Hydrothermal alkaline sulfite pretreatment in the delivery of fermentable sugars from sugarcane bagasse

Abstract

This work aims to demonstrate the importance of hydrothermal alkaline sulfite pretreatment of sugarcane bagasse in the delivery of fermentable sugars. The pretreatment conditions, namely sodium sulfite loads (5.0-10.0 wt%), temperatures (140-160 1C) and reaction times (30-60 min), were tested according to the full factorial design of experiments. The employed pretreatment was characterized by high lignin removal (43-77 wt%) and partial extraction of xylans (up to 25.0 wt%), mainly by cleavage of acetyl and arabinosyl groups. After 72 h of enzymatic hydrolysis with 10 FPU (filter paper unit) cellulase and 10 CBU (cellobiose unit) b-glucosidase per g of pretreated bagasse, the conversion of the carbohydrate-enriched substrates was in the range of 51 to 80 mol% for cellulose and 45 to 71 mol% for xylans. The best hydrothermal alkaline sulfite pretreatment conditions (10.0 wt% sulfite load, 150 1C and 45 min) were found to be highly efficient for the delivery of fermentable sugars with a yield as high as 40.4 AE 1.9 g for 100 g native bagasse.

Enhancing enzymatic saccharification of sugarcane bagasse by combinatorial pretreatment and Tween 80

“…The absent furfural/HMF in the pretreatment liquor also verified the fact that the weak pretreatment conditions were inadequate for the dehydration of xylose/glucose to furfural/HMF. For other degradation components in hemicellulose, the recovery of arabinose and galactose in the pretreatment liquor was higher than that of xylose, suggesting that the arabinan and galactan in hemicellulose were easier to degrade than xylan, which was consistent with previous report that the removal of hemicellulose was ascribed to the cleavage of acetyl and arabinosyl groups [ 20 ]. Meanwhile, the contents of oligomers obtained from hemicellulose degradation were higher than that of monomers, suggesting that lower severity (log R o ) of 2.06 for 30 min and 2.37 for 60 min at 120 °C favored the production of oligomers and was insufficient for the degradation of the generated oligomers to monomers [ 21 ].…”

Impact of ammonium sulfite-based sequential pretreatment combinations on two distinct saccharifications of wheat straw

“…20 mg lignin sample was dissolved in 0.6 mL of D 2 O. The spectral widths were 5000 and 20 000 Hz for the 1 H and 13 C dimensions, respectively. Integration calculations of the 2D contours in all spectra were performed using MestReNova soware.…”

“…3.3.3 2D HSQC NMR analysis of lignin in the spent liquor of AS pretreatment. 2D HSQC NMR technique is a powerful tool for the detailed understanding of lignin structure, allowing for the resolution of overlapping resonances observed in either the 1 H or 13 C NMR spectra. In order to acquire a more complete understanding of the lignin structures, 2D HSQC NMR spectra of lignin samples from the rst step of AS + HT/X pretreatment and the second step of HT + AS pretreatment were comparatively investigated.…”

“…11 Among these approaches, ammonium sulte (AS) pretreatment can efficiently remove lignin of lignocellulose via ammonolysis and sulfonation of lignin, thus enhancing the accessibility of cellulose. 12,13 Also, the spent liquor of AS pretreatment can be used to produce lignin-based fertilizer due to the high nitrogen contents, 14 and the sulfonated lignin can be used to produce other products as well, such as concrete water-reducer, dye dispersant, or surfactant, 7 to further improve the economic feasibility and sustainability of the entire process of AS pretreatment.…”

Produção integrada de monossacarídeos e lignosulfonatos a partir de bagaço de cana-de-açúcar

“…O bagaço de cana-de-açúcar utilizado neste trabalho continha originalmente 20,3 % de lignina total, 40,2% de glucana e 26,9% de hemicelulose (21,6% de xilana, 2,1% de grupos arabinosil e 3,2% de grupos acetil) (Tabela 4). Esses valores estão em conformidade com os dados de composição química de bagaço de cana-de-açúcar reportados na literatura, que são 38-48% para celulose, 25-30% para hemiceluloses e 19-25% para lignina (MASARIN et al, 2011;TAVARES et al, 2018).…”