3.10. Enzymatic Hydrolysis of Xylan

Free- and immobilized MpXyn10 were applied in the hydrolysis of xylans from diverse sources (xylan from beechwood, birchwood, oat spelts, and arabinoxylan). The assays consisted of 0.5% (w/v) xylan in 50 mmol L⁻¹ citrate buffer, pH 5.0, and 0.1 U of xylanase activity in the reaction medium for both preparations. The assays were incubated in a Thermomixer comfort (Eppendorf, Hamburg, Germany) at 50 °C, 1300 rpm. Aliquots were removed over time (0 to 180 min) and boiled at 98 °C for 5 min. The reducing sugars were quantified with the DNS method, and the XOS produced were analyzed with TLC and HPLC. Controls were carried out to evaluate the xylan-derived products in the reaction medium under the same assay conditions.

The XOS yield, % (xylan conversion to xylobiose (X2) and xylotriose (X3) was calculated according to Equation (3):

where C is the concentration (mg mL⁻¹); f_X2 (0.936) and f_X3 (0.956) are stoichiometric factors [21,53,65].