Organosolv fractionation is considered to be an environmentally friendly process to afford substantially cellulose, hemicelluloses/degraded sugars and lignin for further process that is specific to each component. After organosolv fractionation, the recalcitrance of lignocellulosic material is destroyed to some extent regarding cellulose crystallinity, degree of polymerization, lignin structure, lignin removal, hemicelluloses solubilization, etc. The obtained cellulosic residue is an enzyme hydrolyzable substance for the production of biofuels. In addition, it can also be converted into pulp for the production of paper, silk and other modified products through further process. The efficient degradation and dissolution of lignin in organic solvents allow the highly selective delignification of lignocellulosic material without the addition of large amounts of inorganic catalyst. Due to the mild conditions in the extraction process, the lignin dissolved in the liquor is easy to be recovered without complicated purification schemes. The obtained sulfur — free organosolv lignin is an ideal renewable and alternative feedstock for a variety of petrochemical-based chemicals and materials, which have great potential markets as well as high value applications. The dissolved carbohydrates, furfural and HMF, can also be served as feedstocks for some chemicals and polymers.

Acknowledgements The authors wish to express their gratitude for the financial support from the State Forestry Administration (200804015/2010-0400706), the National Natural Science Foundation of China (30930073 and 31070526), Major State Basic Research Projects of China (973-2010CB732204), Ministry of Education (111), and Hei Long Jiang Province for Distin­guished Young Scholars (JC200907).