Abstract: Mild alkaline peroxide pretreatment conditions for rice straw were optimized with a view to increase the ratio of enzymatic saccharification. The results showed that the mild alkaline peroxide pretreatment reduced the content of lignin and increased the content of cellulose of rice straw. The optimal pretreament conditions were as follows : temperature 40 ℃, reaction time 24 h, hydrogen peroxide 2.0 %. Under the optimal conditions, the enzymatic saccharification ratio of the mild alkaline peroxide pretreated rice straw was 83.23 %. The enzymatic saccharification ratio of rice straw pretreated by the alkaline with 2.0 % NaOH, temperature 30 ℃, time 24 h was 70.38 %.The enzymatic saccharification ratio of the mild alkaline peroxide pretreated rice straw is higher evidently than that of the alkaline pretreated rice straw. The results also showed that the removal efficiency of lignin was affected by the mass fraction of hydrogen peroxide. When the mass fraction of hydrogen peroxide is greater than 2.0 %, the selectivity of lignin removal is decreased. Lignin removal remains unchanged, but the loss ratio of hemicelluloses is increased.

Key words: mild alkaline, peroxide, rice straw, pretreatment, enzymatic hydrolysis