The lignocellulosic biomass, such as provided by the sugarcane, is an abundant source of raw materials for energy production. Milling and pretreatments can be employed to alter the structure of the materials, remove lignin, and hemicellulose. This pretreatment effect exposes the cellulose and raises its accessibility, which is one of the most important properties to ensure enzymatic digestibility. However, the biomass generated from the sugarcane has different physicochemical characteristics, giving different responses to the pretreatments. In this context, this study aimed to verify the effects of lignin and hemicellulose removal from the sugarcane biomass (external fraction, node, internode, and leaf) on cellulose accessibility. Each fraction was pretreated with acid (5, 10, and 20% w/w, at 121 °C/30 min), alkali (5, 10, 20, and 30% NaOH w/w) and oxidative (0.5, 1, 2, and 3 h charged with 30% sodium chlorite). Accessibility was determined by dye adsorption of Direct Orange (external specific surface) and Direct Blue (internal specific surface). Enzymatic hydrolysis was used to verify the effects of pretreatments and cellulose accessibility on the glucose yield. Delignification by sodium chlorite (oxidative) resulted in lignin removal, with almost complete removal from leaf samples. Accessibility determined indicated that pretreatments that are more aggressive improved cellulose accessibility. The less recalcitrant fraction, the internode, showed 1333.3 mg/g of Direct Orange adsorbed and 746.3 mg/g of Direct Blue. Glucose yield during enzymatic hydrolysis improved with higher cellulose accessibility. Lignin and xylan removal (down to 10% and 1%, respectively) resulted in higher glucose yield, with delignified internode samples showing almost complete cellulose conversion. Hemicellulose and lignin removal by the pretreatments directly influenced cellulose accessibility, resulting in better enzymatic hydrolysis across all fractions. This study successfully showed that lignin and hemicellulose removal of 15% and 10%, respectively, resulting in at least 60% of glucose yield, reaching desired accessibility levels based on dye adsorption of 2079.6 mg/g.

中文翻译：

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最少地去除木质素和木聚糖，以改善纤维素的可及性

诸如由甘蔗提供的木质纤维素生物质是用于产生能量的原材料的丰富来源。可以使用研磨和预处理来改变材料的结构，去除木质素和半纤维素。这种预处理效果会暴露纤维素并提高其可及性，这是确保酶消化性的最重要特性之一。但是，由甘蔗产生的生物质具有不同的理化特性，对预处理的反应不同。在这种情况下，本研究旨在验证从甘蔗生物量（外部部分，节，节间和叶）去除木质素和半纤维素对纤维素可及性的影响。每个级分均用酸（5、10和20％w / w，在121°C / 30分钟），碱（5、10、20，和30％NaOH w / w）和氧化剂（0.5、1、2和3小时加入30％亚氯酸钠）。通过直接橙（外部比表面）和直接蓝（内部比表面）的染料吸附来确定可及性。酶水解用于验证预处理和纤维素可及性对葡萄糖产量的影响。亚氯酸钠（氧化性）的脱木素作用可去除木质素，几乎可以从叶片样品中完全去除木质素。确定的可及性表明，更具侵略性的预处理可改善纤维素的可及性。难降解程度较小的节间表明吸附的直接橙为1333.3 mg / g，直接蓝为746.3 mg / g。酶促水解过程中的葡萄糖产率提高，纤维素可及性更高。木质素和木聚糖去除率（分别降至10％和1％，分别）导致更高的葡萄糖产量，去木质素的节间样品显示纤维素几乎完全转化。预处理除去半纤维素和木质素会直接影响纤维素的可及性，从而导致所有馏分中的酶水解更好。这项研究成功地表明，木质素和半纤维素的去除率分别为15％和10％，导致至少60％的葡萄糖产率，基于2079.6 mg / g的染料吸附量，达到了所需的可及性水平。