Pilot‐plant production of xylo‐oligosaccharides from corncob by steaming, enzymatic hydrolysis and nanofiltration

Abstract

This paper reports a pilot-plant production process for xylo-oligosaccharides (mainly xylobiose and xylotriose) from corncob meal by steaming treatment followed by enzymatic hydrolysis and nanofiltration. The effects of corncob meal pretreatment, steaming temperature and time were investigated in order to obtain maximum extraction of xylan and to minimize the autohydrolysis of xylan into xylose. The enzymatic reaction was carried out using Aspergillus niger AN-1.15 endo-xylanase at 55• C and the optimum enzymatic hydrolysis time was 5 h. The conventional downstream processing for purification of xylo-oligosaccharides was incorporated with nanofiltration technology, giving benefits of energy saving and removal of monosaccharides. The final product from 40 kg of corncob meal was 10 dm 3 of xylo-oligosaccharide syrup (800 g dm −3 total sugar), containing 74.5% xylobiose and xylotriose.

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

“…Besides the expected increment in concentration, evaporation allows the removal of acetic acid and flavors or their precursors, which can be responsible of off-flavors [8]. Spray-drying and liophilization are widely used for the recovery of hemicellulose oligomers in powder form [40,114].…”

“…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].…”

The Potential of Pre-Hydrolysis Liquor from the Dissolving Pulp Process as Recovery Source of Xylooligosaccharide - A Mini-Review

“…Generally, the purity levels of XOs can be attained through further processing of the hydrolysate (Yuan et al 2004). Liu et al (2011a) used ethanol to precipitate hemicelluloses from PHL in high-yield pulp, in which one liter of prehydrolysis liquor (PHL) was mixed with four liters of ethanol at room temperature.…”

Optimisation of solid-state fermentation of Aspergillus niger JL-15 for xylanase production and xylooligosaccharides preparation

“…The changes in viscosity and reducing sugars from xylan solution rect enzymatic hydrolysis of a susceptible substrate (Katapodis & Christakopoulos 2005), or a combination of chemical and enzymatic treatments (Yuan et al 2004). Out of these methods, enzymatic hydrolysis is more desirable because it does not produce undesirable byproducts or high amounts of monosaccharides and does not require special equipment.…”