Kinetics of exoglucanase and endoglucanase produced by <i>Aspergillus niger</i> NRRL 567

Abstract

In this study we reported for the first time kinetics of exoglucanase (EXG) and endoglucanase (EG) from Aspergillus niger NRRL 567. The optimum pH and temperature for crude EXG and EG was found to be 3.5 and 30°C respectively. Zn²⁺, Ca²⁺, Mn²⁺ and Co²⁺ enhanced the crude activity of EXG and EG whereas Mg²⁺, Fe²⁺ and Hg²⁺ showed various degree of inhibitory effects. Cu²⁺ enhanced crude EXG activity and inhibited crude EG activity. The energy of activation (Ea) for the EXG and EG were 21.20 and 22.52 kJ mol^-1, respectively. The Q₁₀ values obtained for the EXG and EG were 1.38 and 1.4, respectively. These enzymes had lower K_m value that shows their high affinity for the substrates. Overall, the studies demonstrate that these enzymes may be suitable for industrial use.

Key words: Exoglucanase, endoglucanase, kinetics, characterization, Aspergillus niger NRRL 567.