Functional stabilization of cellulase by covalent modification with chitosan

Chitosan was linked to cellulase (EC 3.2.1.4) from Trichoderma viride by covalent conjugation to periodate‐activated carbohydrate moieties of the enzyme. The modified enzyme contained about 1.5 mol of polymer per mol of protein. The specific activity of the conjugate prepared was 39.8% of the native cellulase. The optimum pH and temperature for cellulase remained unaltered after modification. The thermostability was increased by 8.9 °C for the cellulase–chitosan complex. Thermal inactivation at different temperatures ranging from 65 °C to 80 °C was markedly increased for the polymer‐modified enzyme. The stability within the pH range 1.0–3.2 was also improved for the modified enzyme. © 2001 Society of Chemical Industry