The enzymes were incubated with xylan from birchwood and from
oat spelts (Sigma, USA; arabinose residues ≤10%, glucose residues
≤15%, xylose residues ≥70%) at concentrations varying from 4.0 to
30.0 mg·mL-1. The Michaelis–Menten constant (Km) and maximal
velocity (Vmax) were estimated from Lineweaver–Burk reciprocal plots
[27]. Three experiments were carried out for each substrate
concentration in triplicate and the straight line plotted was calculated
by linear regression (Microsoft Office Excel, version 12.0) using mean
values obtained from each experimental point.