Solubilization and Fractionation of Japanese Beech Wood with LiCl and DMSO

The solubility of beech wood cell wall in 8% lithium chloride/dimethyl sulfoxide (LiCl/DMSO) was investigated with an ethylenediamine (EDA) pretreatment without ball milling. EDA pretreatment of the wood cell wall was found to be an efficient method for the solubilization of the majority of the wood cell wall while avoiding the destructive effects of milling on the structure of the wood cell wall components. The yield of the final insoluble fraction was only approximately 31.6% based on the original Wiley wood sample after two EDA pretreatments and the dissolving processes. The solubility of lignocellulosic material in 8% LiCl/DMSO increased with decreasing lignin content after an EDA pretreatment. The yield of the insoluble fraction decreased from 62.9% to 9.2% with a decrease of lignin content from 28.0% to 14.1%. When the lignin content of lignocellulosic material was relatively low (approximately 10.5%), it could be dissolved in 8% LiCl/DMSO after an EDA pretreatment. The EDA pretreatment of wood meal had a much greater effect on polysaccharides than on the lignin in wood cell wall.