Amount of free β-glucosidase activity in experiments with addition of different substrates. No substrate (reference); filter paper (cellulose); arabinoxylan (hemicellulose); lignin, PWS lignin (lignin from pretreated wheat straw) and PWS (pretreated wheat straw containing a mixture of cellulose, hemicellulose and lignin). Substrate loadings: cellulose, 24 mg/mL; hemicellulose, 2 mg/mL; lignin, 15 mg/mL; and pretreated wheat straw, 48 mg/mL. Enzyme dosage: 500 nkat/mL. The activities are relative to the control without added substrate for each enzyme.