Enhancement of Endoglucanase Activity through Incorporation of Physical, Chemical, and Combined Mutagenesis in Thermophilic Strain of Aspergillus fumigatus

An indigenous Aspergillus fumigatus strain was subjected to physical, chemical, and combined mutagenesis to enhance endoglucanase production. Using rice straw as a greater carbon source, maximum activity (84.94 U mL –1 ) was achieved via 10-minute UV exposure, while 150 µg mL –1 ethyl methane sulphonate (EMS) yielded 62.89 U mL –1 . Combined mutagenesis (10 min UV+ 150 µg mL –1 EMS) significantly improved activity to 123.32 U mL –1 , a 2.2-fold increase over the wild type. Optimization through response surface methodology (RSM) identified optimal conditions: pH 5.0, 55 °C, 5-day incubation, and 5 mL inoculum. Purified endoglucanase exhibited high affinity for CMC and was further activated by 300 mM CaCl 2 to 176.92 U mL –1 . Kinetic and characterization studies confirm that this thermophilic, genetically improved (physical