为了提高甘蔗渣的酶解率和总糖收率,设计高温液态水耦合氨法预处理方法。与单一高温液态水预处理相比,耦合预处理木质素脱除率从23.12%提高至75.36%,残渣酶解率从77.96%提高至97.99%,总糖收率从81.30%提高至87.85%。耦合处理后甘蔗渣原料紧密有序的纤维结构被破坏得更厉害,细胞壁各层界线难以区分,其中耦合处理第一步反应对残渣表面形态和细胞超微结构影响较大,随后第二步脱木质素或者脱半纤维素效果减弱。梯度酶解试验表明,原料中木质素的脱除对于减少加酶量和提高酶解率至关重要。
A pretreatment combined liquid hot water and aqueous ammonia was investigated to improve the enzymatic digestibility and total sugar recovery of sugarcane bagasse. Compared with single liquid hot water pretreatment, the lignin removal was increased from 23.12% to 77.96%, the enzymatic digestibility of the residual solids was increased from 75.36% to 97.99% and the total sugar recovery was increased from 81.30% to 87.85% for combined pretreatment. The fibers of treated samples were separated from the initial connected structure and fully exposed, and the boundaries among the three layers in the secondary wall could not be exactly distinguished. Moreover, the first step in the combined pretreatment had a greater influence on the change of surface morphology and ultrastructural characteristics of the residual solids, and the removal of lignin and hemicellulose was weakened in the second step of the pretreatment. The results of enzymatic hydrolysis under different cellulose loading indicate that the delignification is very important for reducing the use of enzyme and improving the digestibility.