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研究了在氨水中添加少量KOH或K3PO4预处理慈竹机械浆(RMP)的工艺。考察了预处理条件对酶解还原糖产率的影响。单因素实验得到氨水加KOH最佳预处理条件为:预处理温度120℃、固液比〔即1 g绝干浆加入液体的体积(mL),下同〕1∶6、时间3.5 h、氨水用量70%(即氨水质量占绝干浆质量的百分数,下同)、KOH用量5%(即KOH质量占绝干浆质量的百分数,下同)。在此最佳条件下,慈竹RMP的纤维素保留率为90.66%,半纤维素保留率为92.90%,木质素脱除率为41.05%;在pH=4.8、加酶量20 FPU/g预处理后底物、反应温度50℃的条件下酶解24 h,还原糖产率为23.95%,纤维素转化率为44.61%。虽然氨水加K3 PO4预处理酶解纤维素转化率可达56.95%,但是纤维素保留率仅为74.59%,与氨水加KOH相比,纤维素损失较大。
The process of pretreatment of mechanical pulp (RMP) with KOH or K3PO4 in aqueous ammonia was studied. The effects of pretreatment conditions on the yield of enzymatically reduced sugar were investigated. The best pretreatment conditions of ammonia water and KOH obtained by single factor experiment are as follows: pretreatment temperature is 120 ℃, solid-liquid ratio 〔1 g dry liquid volume (mL), the same below〕 1: 6, time 3.5 h, ammonia The amount of 70% (that is, the quality of ammonia water accounted for the percentage of dry pulp, the same below), KOH dosage 5% (ie, KOH mass percentage of dry pulp quality, the same below). Under these optimal conditions, the retention rate of cellulose in RMP was 90.66%, the retention rate of hemicellulose was 92.90% and the lignin removal rate was 41.05%. At pH 4.8, the amount of enzyme was 20 FPU / g After treatment, the substrate was hydrolyzed at 50 ℃ for 24 h, the yield of reducing sugar was 23.95% and the cellulose conversion was 44.61%. Although the ammonia conversion plus K3 PO4 pretreatment could reach 56.95%, the retention rate of cellulose was only 74.59%. Compared with ammonia plus KOH, cellulose lost more.