Cascade temperature-arising strategy for xylo-oligosaccharide production from lignocellulosic biomass with acetic acid catalyst recycling operation

Abstract

Acetic acid acidolysis had so far been performed as a green technology to produce high value-added xylo-oligosaccharide from lignocellulosic residues while around 30% inert xylan-constitute is still retained. For improving economic and environmental benefits, a cascade temperature-arising technical strategy was designed and developed for the co-production of xylo-oligosaccharide and enzymatic-hydrolyzed glucose by a continuous two-step acidolysis mode with the recyclable acetic acid catalyst. The combined process was optimized by uniform design experiments and temperature plays the key factor for xylo-oligosaccharide yield and xylose-chemicals degradation. We obtained respectively 63.41% and 61.44% xylo-oligosaccharide yield from corncob and wheat straw during continuous two-step acidolysis with acetic acid recycling operation at 140 °C and 190 °C, which increased by 52.03% and 76.55% than the one-step process. Meanwhile, the corresponding enzymatic hydrolysis yield was increased to 100% and 98.2%. In short, the two-step cascade temperature-rising acidolysis technology can maximize the utilization of hemicellulose and cellulose constitutes and fully explore the value-added utilization of lignocellulosic biomass. The cascade temperature-arising technical strategy does therefore demonstrate something for the more efficient and green utilization of lignocellulosic biomass.