Study of charcoal adsorption for improving the production of Xylitol from wood hydrolysates

Abstract

Xylose-containing solutions, obtained from acid prehydrolysis of Eucalyptus wood, were treated with powdered charcoal in order to remove lignin-derived compounds that limit the potential of hydrolysates for making fermentation media. Both the kinetics and equilibrium of adsorption were modelled using equations reported in literature. Charcoalpretreated hydrolysates were supplemented with nutrients and used for producing xylitol with the yeast Debaryomyces hansenii NRRL Y-7426. The susceptibility to fermentation of culture media made with this procedure was compared with those corresponding to media made from untreated wood hydrolysates or standard xylose solutions. The removal of lignin-derived compounds from hydrolysates was closely related with the efficiency of fermentation.

Evaluation of the activated charcoals and adsorption conditions used in the treatment of sugarcane bagasse hydrolysate for xylitol production

“…However, in the study of adsorption operational conditions for improvement of wood hydrolysate fermentability Parajó et al (1996b) verified that the effect of activated charcoal concentration is about three times higher than that of temperature on D-xylose-toxylitol conversion (Y P/S ).…”

“…With regard to contact time, the fixed value of 30 min was the same as that in a study on wood hydrolysate treatment with activated charcoal; Parajó et al (1996b) reported that irrespective of the hydrolysate:charcoal ratio, 400g/g or 20g/g, the maximum phenol adsorption on activated charcoal occurred in about 30min of contact time. The same authors observed that, after a fast initial period of up to about 30min and a slow stage, the surface area of the activated charcoal was progressively blocked during the process.…”

Recovery, concentration and purification of phenolic compounds by adsorption: A review

“…Aspen wood autohydrolysates Zeolites Ranjan et al (2009) Brewery's spent grain hydrolyzates from autohydrolysis-acid hydrolysis Activated charcoal Anionic exchange resin Cationinc exchange resin Carvalheiro et al (2005) Corn cob acid hydrolyzates Activated charcoal Rivas et al (2002) and Berson et al (2005) Anionic exchange resin Domínguez et al (1997a) Anionic exchange resin Cationic exchange resins de Mancilha and Karim (2003) Eucalypt wood acid hydrolyzates Activated charcoal Parajó et al (1995Parajó et al ( , 1996Parajó et al ( , 1997a, Diz et al (2002), Canilha et al (2004), Carvalho et al (2006) and Villarreal et al (2006) Diatomaceous earths Carvalho et al (2006) Anionic exchange resin Canilha et al (2004) and Carvalho et al (2006) Watson et al (1984), van Zyl et al (1991 and Chandel et al (2007) Sugarcane bagasse acid impregnated steam explosion hydrolyzate Activated charcoal Roberto et al (1991) Wheat straw acid hydrolyzates Activated charcoal Canilha et al (2006Canilha et al ( , 2008 Xylooligosaccharides (XO) can be produced from xylan-rich materials by chemical and/or enzymatic treatments (Moure et al, 2006), yielding a number of byproducts. To obtain food-grade XO, liquors from hydrothermal treatments have to be processed to remove unwanted components, for example by adsorption onto ACs, acid clay, bentonite, diatomaceous earth, aluminium hydroxide or oxide, titanium, silica and porous synthetic materials (Montané et al, 2006;Moure et al, 2006;Zhu et al, 2006;Makishima et al, 2009).…”

Autohydrolysis of agricultural by-products for the production of xylo-oligosaccharides

“…Extraction with organic solvents, followed by a secondary treatment like ion exchange, lead the best results for the purification of xylo-oligosaccharides from rice husks, and from solid residues coming from the malting industry [33,34,38]. Adsorption onto activated carbons [39], and nanofiltration [40], are promising methods for the separation of lignin-derived compounds produced by autohydrolysis reaction. …”

“…[38]. Xylan of relatively high molar mass obtained from several sources (aspenwood and birchwood) was converted to hydrogel by reaction with chitosan [39,40], and it was also used for the preparation of nanoparticles for drug release on oral administration [41]. In a completely different procedure, hemicelluloses from spruce were chemically modified and reacted with poly(2-hydroxyethyl methacrylate) (PHEMA) for the preparation of hydrogels [42].…”