The influence of temperature upon the hydrolysis of cellobiose by β-1,4-glucosidases from Aspergillus niger

We have made experimental studies into the enzymatic hydrolysis of cellobiose within the temperature range of 40°C to 70°C at pH 4.9, by using β-1,4-glucosidase from Aspergillus niger. At 70°C there was significant enzyme deactivation, which could be fitted to a potential deactivation model with values of n equal to 1.09 and kd to 0.1564 (g/l)−0.09 min−1, whereas the rate of hydrolysis could be fitted to the Michaelis–Menten equation. Between 40°C and 60°C we noted a substrate inhibition and that the CEC compound formed contributed to glucose production. The apparent activation energies had values of 4.66, 8.45, 4.82, and 3.99 kJ/mol for the kinetic constants ka and ka2 the Michaelis constant and the substrate inhibition constant, respectively.