Abstract: Lignocellulose contains abundant polysaccharides. The depolymerization of lignocellulose into oligosaccharides under relatively mild conditions not only retains their natural structures, but also reduces energy inputs during the cleavage of chemical bonds, which is promising for the development of the sustainable biorefinery industry. Here, we summarized the catalytic depolymerization of the polysaccharides by using acidic catalysts, mainly including inorganic acids, organic acids and inorganic salts. The effects of catalysts and the products' structural features were compared. Owing to their appropriate molecular size and abundant oxygen-containing groups, the oligosaccharides could be modified and then used as aldehyde tanning agents and metal-oligosaccharides complex tanning agents. We summarized the modification methods and modification degrees for improving the tanning performance, providing the application potentials of these biomass-derived tanning agents in high-performance chrome-free leather production.

Key words: oligosaccharides, lignocellulose, homogeneous catalysis, leather tanning