Improvement of enzymatic saccharification of sugarcane bagasse by dilute-alkali-catalyzed hydrothermal treatment and subsequent disk milling

Dilute-alkali-catalyzed hydrothermal treatment (HT) was conducted to improve the enzymatic degradability of sugarcane bagasse. Wet-disk milling (DM) was also performed after HT. Sodium carbonate with 0–6% concentration on dry weight basis of bagasse was used as the alkali catalyst. A content of more than 4% of the alkali catalyst was necessary for producing a higher amount of glucose than that produced after HT without an alkali catalyst. HT with 6% of the alkali catalyst, which decreased the pH to the neutral region, retained more xylan and less lignin than HT without an alkali. Subsequent DM improved the enzymatic degradability further and increased the specific surface area. For a substrate concentration of 10%, the amounts of glucose and xylose produced were 344 and 188 mg/g-bagasse, respectively. These values corresponded to yields of 77% and 67% on the basis of the glucan and xylan contents in raw bagasse, respectively.

► Dilute-alkali treatment was conducted before wet-disk milling of Brazilian bagasse. ► The alkali treatment retained more xylan and less lignin than just water treatment. ► The disk-milling method promoted enzymatic degradation as the ball-milling method. ► Specific surface area increased after disk milling. ► The treated bagasse was saccharified to sugars under high solid concentration (10%).