Effective Utilization of Moso-Bamboo (Phyllostachys heterocycla) with Hot-Compressed Water

Abstract

In this study, the hydrothermal carbonization behavior of bamboo in hot-compressed water (HCW) using a batch-type reactor at 180–300 °C was observed to investigate the effective utilization of bamboo as a biomass resource. Polysaccharides (hemicellulose and cellulose) in the bamboo were changed to water soluble products. At 180–220 °C, hemicellulose (arabinoxylan) was first hydrolyzed to xylooligosaccharides and then to xylose that was further decomposed to various organic acids and furfural. However, most of the cellulose was not decomposed and was recovered as a solid residue at this temperature range. Cellulose began hydrolyzing to glucose at temperatures above 240 °C. The glucose was further decomposed to various organic acids and 5-HMF. The recovered oligosaccharides and monosaccharides can be used as functional food, food additives, and feedstocks for ethanol and lactic fermentation. Furthermore, organic acids and furans can be used as various chemicals. More hemicellulose and cellulose, which have relatively low carbon content in the bamboo, were decomposed and dissolved in water. As a result, the solid residue consisted mainly of lignin, which has higher carbon content compared to cellulose and hemicellulose. Hence, the heating value of the solid residue increased at higher temperature during treatment and the residue could be considered as a solid fuel.