Abstract: Combination of thermo-mechanical pulping (TMP) process and liquid hot water pretreatment method had been adopted to improve the enzymatic saccharification efficiency and reduce the processing costs of eucalyptus. The pretreated sample was then hydrolyzed by cellulase. The pretreatment conditions on the influence of sugars yield had been discussed by measuring the yield of xylose and glucose in the pretreated hydrolyzate and enzymatic hydrolyzate. The optimal pretreatment condition was 180℃(cooking temperature), 40 min(residence time) and 5%(substrate concentration). It was obtained by using the total sugars in the pretreated hydrolyzate and enzymatic hydrolyzate as the evaluation index. Under this pretreatment condition, the conversion of xylose and glucose reached 82.70% and 78.90%, respectively. The physics and chemical properties of pretreated residue were characterized using FT-IR, SEM so as to analyse effect of two pretreatment methods. The results showed that the particle of raw eucalyptus was diminished, the shape was filiform, but the fibre morphology was maintained. However, the structure of fibre was loose and smashed after the hot water pretreatment, and this improved the accessibility of cellulase and efficiency of enzymolysis.

Key words: eucalyptus, TMP, hot water pretreatment, enzyme hydrolysis, FT-IR, SEM