Abstract

In the present study, the cellulose from sugarcane tops (SCT) was separated and characterized for its purity. Approximately, 85% (w/w) of total cellulose present in raw SCT was recovered by using alkaline method. The monosaccharide analysis of SCT cellulose by HPLC showed 91% D-glucose, 7.5% D-xylose and 1.5% D-arabinose residues. Surface morphology study of dried cellulosic fibers by FESEM exhibited the fibrous structure. The FTIR analysis of separated cellulose displayed the peaks corresponding to the peaks obtained from commercial cellulose, confirming its purity. The crystallinity index (CrI) of separated cellulose increased to 49% after delignification and xylan extraction from 36% of raw SCT. The typical TGA curve of separated SCT cellulose showed decomposition and mass reduction at 327 °C resulting in single decomposition peak in TGA analysis, confirming its purity. CHNS analysis supported the purity of separated cellulose by confirming absence of nitrogen and sulfur. The separated cellulose was hydrolyzed by recombinant endo-β-1,4-glucanase (CtCel8A), cellobiohydrolase (CtCBH5A) from Clostridium themocellum and β-1,4-glucosidase (HtBgl) from Hungateiclostridium thermocellum at pH 5.8, 50 °C for 24 h, resulting in the production of 188 mg/g of total reducing sugar (TRS). The separated cellulose from SCT can be utilized as an alternative substrate for commercialization and for bioethanol production.

摘要

在本研究中，对来自甘蔗顶部 (SCT) 的纤维素进行了分离，并对其纯度进行了表征。使用碱性方法回收了大约 85% (w/w) 的粗 SCT 中存在的总纤维素。通过HPLC对SCT纤维素的单糖分析显示91%的D-葡萄糖、7.5%的D-木糖和1.5%的D-阿拉伯糖残基。通过 FESEM 对干燥纤维素纤维的表面形态研究显示出纤维结构。分离出的纤维素的 FTIR 分析显示出与从商业纤维素获得的峰相对应的峰，证实了其纯度。结晶度指数（CrI) 的分离纤维素在脱木素和木聚糖提取后从 36% 的原始 SCT 增加到 49%。分离的 SCT 纤维素的典型 TGA 曲线显示在 327 °C 下分解和质量减少，导致 TGA 分析中的单个分解峰，证实了其纯度。CHNS 分析通过确认不存在氮和硫来支持分离的纤维素的纯度。分离的纤维素被重组内切-β-1,4-葡聚糖酶（Ct Cel8A）、来自热纤梭菌的纤维二糖水解酶（Ct CBH5A）和来自热纤梭菌的β-1,4-葡糖苷酶（Ht Bgl）水解在 pH 5.8、50 °C 下 24 小时，产生 188 mg/g 的总还原糖 (TRS)。从 SCT 中分离出的纤维素可用作商业化和生物乙醇生产的替代底物。