Effect of pretreatment reagent and hydrogen peroxide on enzymatic hydrolysis of oak in percolation process

The effect of pretreatment reagent and hydrogen peroxide on enzymatic diges tibility of oak was investigated to compare pretreatment performance. Pretr eatment reagents used were ammonia, sulfuric acid, and water. These solutio ns were used without or in combination with hydrogen peroxide in the percol ation reactor. The reaction was carried out at 170 degreesC for the predete rmined reaction time. Ammonia treatment showed the highest delignification but the lowest digestibility and hemicellulose removal among the three trea tments. Acid treatment proved to be a very effective method in terms of hem icellulose recovery and cellulose digestibility. Hemicellulose recovery was 65-90% and digestibilities were > 90% in the range of 0.01-0.2% acid conce ntration in both treatments, hydrogen peroxide had some effect on digestibi lity but decomposed soluble sugars produced during pretreatment. Unlike amm onia and acid treatments, hydrogen peroxide in water treatment had a certai n effect on hemicellulose recovery as well as delignification. At 1.60% hyd rogen peroxide concentration, both hemicellulose recovery and digestibility were about 90%, which were almost the same as those of 0.2% sulfuric acid treatment. Also, digestibility was investigated as a function of hemicellul ose removal or delignification. It was found that digestibility was more di rectly related to hemicellulose removal rather than delignification.