Abstract: In order to improve the effect of enzymatic saccharification of eucalyptus wood, eucalyptus lignocellulose was pretreated by an alkaline sulfite pretreatment. The obtained samples were conducted for cellulose enzymolytic saccharification. According to the sugars yield in the enzymolysis liquid, the influence of pretreatment conditions on the reducing sugars yield was discussed. The results showed that with the increases of cooking temperature and NaOH dosage, both the glucose and xylose yields increased obviously in the enzymolysis liquid. Both glucose and xylose yields increased at first, then decreased. When the heating time and Na₂SO₃ dosage increased. The optimal pretreatment conditions are as follows: cooking temperature 170 ℃, sodium sulfite charge 10 %, sodium hydroxide charge 3 %, reaction time of temperature keeping 3 h. In addition, the yields of glucose and the xylose reached 60.79 % and 15.37 %, which are 3.93 and 7.88 times higher than that of the untreated, respectively.

Key words: eucalyptus wood, alkaline sulfite pretreatment, enzymolysis, sugars yield