Valorization of Corn Straw for Production of Glucose by Two-Step Depolymerization

Graphical A two-step depolymerizing strategy of high-pressure CO 2 −H 2 O pretreatment and oxidation-hydrolysis is applied for selective degradation of corn straw to glucose production. As high as 32.2 % yield of glucose is achieved without additional catalyst and the active acid sites generated during the partial oxidation on glucose units of cellulose is crucial. Depolymerization of the cellulose part in lignocellulose to glucose is a significant step for lignocellulose valorization. As one of the main by-products of agricultural biomass in crop-producing filed, valorization of corn straw has attracted considerable attention. In this study, a two-step depolymerizing strategy of high-pressure CO 2 −H 2 O pretreatment and oxidation-hydrolysis was applied for selective depolymerization of the cellulose component of corn straw to glucose production. Most part of the hemicellulose component could be removed through high-pressure CO 2 −H 2 O pretreatment in the presence of low concentration of acetic acid, and then as high as 32.2 % yield of glucose was achieved in water at 170 °C for 6 h without additional catalyst. The active acid sites generated during the partial oxidation of hydroxymethyl groups to carboxyl groups on glucose units of cellulose was shown to be crucial for the efficient valorization of corn straw for glucose production.