the pretreatment process was complicated and required much time. In our CHEMEX pretreatment, 83.6% enzymatic digestibility was obtained at 130 °C for 20 min with 2.9 M sodium hydroxide. In general, acid and thermal pretreatment require high temperature and short time. In comparison, alkali-catalyzed pretreatment requires lower temperature and longer time. Increase of enzymatic digestibility due to dilute NaOH treatment is caused by the swelling of biomass, leading to an increase in the internal surface area, a decrease in crystallinity, the separation of structural linkages between lignin and carbohydrates, and the disruption of the lignin structure [22] and [23].