The physical and chemical properties of pretreatment residue were characterized with FT-IR, SEM, XRD, et al. The pre-processing process of eucalyptus in high temperature liquid water was optimized. The results show that the optimal pretreatment conditions are as follows: temperature 180 ℃, time 20 min, liquid solid ratio 20:1. The conversion ratio of xylose is 81.93 % under above optimal conditions. After optimal pretreatment, most of hemicellulose were hydrolysed, but there was a little change in the crystalline degree of cellulose. Scanning electron microscope images showed that the hot water pretreatment caused the relaxation of carbohydrate of eucalyptus, the breakage of pit membrane and the increase of fiber fragments. These significantly improved the accessibility of cellulase. It was also found that further enzymolysis of optimized pre-treatment residue improved glucose conversion to 80.52% , which increased by 3.63 times compared with these raw residue. The further analysis of enzymatic residue indicated that 87.12% acid insoluble lignin from eucalyptus could be recycled, which was conducive to the comprehensive utilization of lignin.%为优化桉木高温热水预处理的工艺条件,用傅立叶红外光谱(FT-IR)、扫描电镜(SEM)、X射线衍射(XRD)等手段分析预处理渣的理化特性.结果表明,最佳的预处理条件为:预处理温度180℃,时间20 min,绝干木粉与水1∶20(g∶ mL).此条件下,预处理液中木糖、葡萄糖的转化率分别为81.93％和2.21％.桉木木粉经最优条件预处理后,大部分半纤维素被水解；纤维素的相对结晶度基本不变；碳水化合物的结构变的松散,纹孔膜破裂,纤维碎片增多,极大的提高了后续纤维素酶的可及度.对最优条件下预处理渣的进一步酶解:发现葡萄糖的转化率高达80.52％,比未经预处理直接酶解提高3.63倍.对酶解残渣的进一步分析可知,桉木原料87.12％的酸不溶木质素可在酶解残渣中得到回收,这有利于木质素的综合利用.
展开▼
