Departamento de Biotecnologia, Escola de Engenharia de Lorena, Universidade de São Paulo, 12602-810, Lorena, SP, Brazil.
Carbohydr Res. 2020 Jun;492:108003. doi: 10.1016/j.carres.2020.108003. Epub 2020 Apr 8.
Hemicellulose-rich substrates produced in the lignocellulose biorefinery context can yield macromolecular xylan structures with assorted application in the chemical industry. Xylan presents natural affinity to cellulose and its incorporation onto fibers increases the physical processability of pulp; however, current studies diverge on how molar mass affects xylan interaction with cellulose. In the current work, xylans with varied structural characteristics were prepared from alkaline-sulfite pretreated sugarcane bagasse with aid of an alkaline-active xylanase and selective precipitations using different ethanol concentrations. Prepared xylan fractions, containing low levels of lignin contamination (4-9%) and molar masses ranging from 2.3 kDa to 34 kDa, were incorporated onto eucalyptus pulp fibers up to 4.7 g xylan/100 g pulp. The efficiency of xylan incorporation onto cellulosic fibers was dependent on the xylan structures, where low molar mass and low substitution degree favored high incorporation levels.
木质纤维素生物炼制过程中产生的富含半纤维素的底物，可以得到具有各种应用的大分子木聚糖结构。木聚糖与纤维素具有天然亲和力，将其掺入纤维中可以提高纸浆的物理加工性能；然而，目前的研究在摩尔质量如何影响木聚糖与纤维素的相互作用方面存在分歧。在本工作中，利用碱性活性木聚糖酶和不同乙醇浓度的选择性沉淀，从碱性亚硫酸盐预处理的甘蔗渣中制备了具有不同结构特征的木聚糖。制备的木聚糖级分，含有低水平的木质素污染（4-9%）和摩尔质量从 2.3 kDa 到 34 kDa 不等，被掺入到桉树木浆纤维中，木聚糖的用量最高可达 4.7 g/100 g 纸浆。木聚糖掺入纤维素纤维的效率取决于木聚糖的结构，其中低摩尔质量和低取代度有利于高掺入水平。
