305 research outputs found
Cold sodium hydroxide/urea based pretreatment of bamboo for bioethanol production: characterization of the cellulose rich fraction
No full textBamboo (Neosinocalamus affinis) was subjected to successive pretreatments to isolate cellulose rich fractions for further utilization. In this study, the ball-milled bamboo underwent ultrasound treatment in ethanol solution at 20 °C for 0, 5, 15, 35, and 50 min, respectively. Then the samples were dissolved with 7% NaOH/12% urea solutions at ?12 °C, followed by successive extractions with dioxane, ethanol, and dimethyl sulfoxide (DMSO). The yields of the obtained cellulose rich fractions ranged from 75.1 to 77.7%. In addition, the structural features of the cellulose rich fractions and the original ball-milled sample were comparatively characterized with a set of spectroscopy and wet chemistry methods including FT-IR, CP/MAS 13C NMR, XRD, SEM, sugar analysis, etc. The results showed that the successive pretreatments resulted in partial removal of carbohydrates and lignin. The lignin released during the pretreatments could facilitate the removal of lignin, which was mainly composed of G and S types. The removal of acetyl groups suggested a decrease of the satirical barrier of enzyme absorption to cellulose. The cellulose rich fractions appeared looser and exhibited more internal surfaces compared to the ball-milled sample. The changes of chemical structures and morphology of the treated sample suggested that the cold sodium hydroxide/urea based pretreatments effectively disrupted the recalcitrance of bamboo, generating highly reactive cellulosic materials for enzymatic hydrolysis to produce bioethano
Extracción de lignanos de carbón leonarditico por los metodos sosa- cloruro de sodio y run-cang sun y determinación de su actividad antioxidante
No full textEste trabajo busca extraer de dicha matriz ácidos húmicos por el método de Run Cang Sun, y el método de sosa – cloruro de sodio, una vez extraídos, fragmentarlos y solubilizarlos para determinar su poder antioxidante. Ya que es conocido que una vez fragmentado los ácidos húmicos se obtienen lignanos y estos poseen grandes cualidades que prestan beneficio a la salud humana. En el presente estudio se hace una breve descripción del estado del arte, sobre los ácidos húmicos, la descripción de las características del carbón objeto de estudio; finalizando con una descripción de la metodología empleada para el desarrollo del estudio, los resultados obtenidos y las conclusiones a las que se llegó
DETOXIFICATION AND SEPARATION OF LIGNOCELLULOSIC BIOMASS PRIOR TO FERMENTATION FOR BIOETHANOL PRODUCTION BY REMOVAL OF LIGNIN AND HEMICELLULOSES
No full textLignocellulosic materials such as agricultural residues have been recog-nized as potential sustainable sources of mixed sugars for fermentation to bioethanol. To obtain a high overall ethanol yield and achieve an economically feasible production process, the removal of lignin and hemicelluloses improves the accessibility of cellulosic material to hydro-lytic enzymes and avoids the degradation products that are inhibitory to the yeast used in the subsequent fermentation. Technological advances, e.g., environmentally friendly removal of lignin and hemicelluloses from lignocellulosic biomass prior to fermentation of the librated glucose from cellulose into bioethanol, has the potential to provide for sustainable and cost effective production of biofuel
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