Enzymatic extraction of xylans from alkaline-sulfite pretreated
sugarcane bagasse and their incorporation onto eucalyptus kraf pulps
Abstract
Hemicellulose-rich substrates produced in the lignocellulose biorefinery
context can yield macromolecular hemicellulose structures with assorted
application in the chemical industry. In the current work,
alkaline-active xylanase aided to extract a varied group of xylan
fractions from alkaline-sulfite pretreated sugarcane bagasse. Extraction
yields (12-44%) depended on the reaction time and the xylanase load
used in the extraction procedure. Prepared fractions contained low
levels of lignin contamination (4-9%) and 4-O-methyl glucuronic acid
arabinoxylan structures. Molar masses of fractions ranged from 2.3 kDa
to 34 kDa. Prepared xylans were incorporated onto eucalyptus pulp fibers
up to 4.7 g xylan/100 g pulp. The efficiency of xylan incorporation was
dependent on the xylan structures, where low molar mass and low
substitution degree favored high incorporation levels. Enzymatic xylan
extraction proved a distinguishing procedure to add value in the
lignocellulosic biorefinery chain of sugarcane bagasse once extracted
xylans are suitable for incorporation onto cellulosic fibers.