Comparative study of lignins from ultrasonic irradiated sugar‐cane bagasse

Abstract

After ultrasonic irradiation of sugar-cane bagasse (SCB) in distilled water at 55 • C for 40 min and continuing stirring for 80 min, the irradiated SCB was sequentially treated with 0.5 M NaOH, 0.5 %, 1.0 %, 1.5 %, 2.0 % and 3.0 % H 2 O 2 at pH 11.5, and 2 M NaOH at 55 • C for 2 h, which solubilized 3.3, 59.7, 15.5, 4.4, 5.5, 1.7, 0.6 and 0.6 % of the original lignin, and 13.4, 38.2, 11.9, 4.5, 9.0, 2.4, 1.2, and 11.3 % of the original hemicelluloses, respectively. In total, the sequential extractions resulted in a release of 91.2 % of the original lignin and 91.9 % of the original hemicelluloses, which were higher than in the case of corresponding extractions without ultrasound pre-treatment. The eight lignin fractions were comparatively characterized by chemical composition, structural features, molecular weights, and thermal stability using alkaline nitrobenzene oxidation, acid hydrolysis, UV, FT-IR, 1 H and 13 C NMR spectroscopy, GPC, and thermal analysis. Compared to the lignins obtained without ultrasound, the lignin fractions prepared with the assistance of ultrasound had the same primary structure, composition, and similar or slightly higher purity.

Solubilization of Lignin Components of Food Concern From Sugarcane Bagasse by Alkaline Hydrolysis Disolución De Componentes Lignínicos De Interés Alimentario a Partir De Bagazo De Caña De Azúcar Por Hidrólisis Alcalina

“…Bagasse is a waste produced when sugar is extracted from sugarcane, typically in a moisture and ash free condition; it generally contains 33-48% cellulose, 19-43% hemicelluloses and 6-32% lignin, its composition normally depending on the region and growth conditions. Table 2 lists the most representative compositions founds in the literature for different batches of sugarcane bagasse (Varhegyi and Antal, 1988;Aiello et al, 1996;García-Pérez et al, 2002;Sun et al, 2004;Xu et al, 2006). Table 3 shows the percent composition of sugarcane bagasse extract obtained by acid hydrolysis with H 2 SO 4 .…”

Understanding the Mechanism of Cypress Liquefaction in Hot-Compressed Water through Characterization of Solid Residues

“…The typical FT-IR spectra of the acid-insoluble lignin and the AISRs obtained at various temperatures are shown in Figure 5b. According to the literatures [24][25][26], the bands at 1599, 1504, and 1415 cm is due to methoxyl C-H deformations and bending of lignin. In the wavenumber region from 1200 to 1300 cm almost disappeared after 280 °C.…”

Lignocellulosics as a Renewable Feedstock for Chemical Industry: Chemical Hydrolysis and Pretreatment Processes

“…For instance, warm season grasses are reported to have both lignified cell walls as well as high levels of phenolic acid esters linked to arabinose [73]. In addition, warm season grasses contain ferulic acid esterified with hemicelluloses and etherified with lignin whilst p-coumaric acid is esterified with lignin [74]. Each of these linkages, in addition to the structure and quantity of lignin present, has a substantial effect on digestibility through both the covalent linkages themselves and the effect they have of physically reducing access to the carbohydrate polymers [75].…”

“…Application of ultrasonic pretreatment used during the isolation of plant materials has been found to significantly improve the extraction of polysaccharides, particularly for extracting low molecular weight hemicelluloses, phenolic acids, and aldehydes from pretreated materials [74,307]. The mechanical effects of ultrasound provide a greater penetration of solvent into cellular materials and improve mass transfer [308].…”

“…Ultrasonic pretreatment has been used for fractionation of hemicellulose from wheat straw and sugarcane bagasse and fractionation of lignin from sugarcane bagasse [74,307]. Application of ultrasonic pretreatment is usually combined with dilute alkaline or oxidation pretreatment to achieve better outcomes [74,307].…”