Effect of Ammonia Pretreatment on Enzymatic Sugar Production from Corn Stover

To make comprehensive use of maize stover, cellulase degradation of maize stover was accelerated. In this paper, maize straw was used as raw material, and reducing sugar yield was the main indicator. The reducing sugar yield was determined by the DNS method after enzymatic digestion of maize straw by ammonification pretreatment, and the effects of ammonification agent type, concentration, solid content and ammonification time on the enzymatic sugar production from maize straw were investigated. The results showed that the highest reducing sugar yield of 314.18 mg/mL was achieved under this condition with ammonium carbonate as the ammoniating agent, ammoniating agent concentration of 20%, solid content of 50% and ammoniating time of 11 d, which was 51.80% higher compared to direct enzymatic digestion of the straw. In addition, it was found by SEM that the structure of lignin and cellulose changed after the ammoniated pretreatment of rice straw with ammonium carbonate, with the surface structure becoming rough and loose and the cellulose exposed, which was more favorable to the action of cellulase. In addition, FTIR revealed that the absorption peaks of maize straw at 2920 and 1650 cm⁻¹ were weakened after ammoniation treatment, and the reduction of their peaks represented to some extent the destruction of the lignin structure. Overall, the enzymatic digestion of maize stover was more favorable after the ammoniated pretreatment of maize stover with ammonium carbonate.