*2.2. Substrates*

Carboxymethylcellulose (CMC, sodium salt, medium viscosity), birch glucuronoxylan, *p*-nitrophenyl-β-D-glucopyranoside, and cellobiose were purchased from Sigma (St. Louis, MO, USA); Avicel PH105 cellulose was from Serva (Heidelberg, Germany); filter paper No.1 was from Whatman (Little Chalfont, UK).
