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

W. Mughal, M. Zafar, A. Anees, Z. Anwar, M. N. Zafar, M. Zubair and S. H. Sumrra

Abstract
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 CaCl2 to 176.92 U mL–1. Kinetic and characterization studies confirm that this thermophilic, genetically improved (physical, chemical, and combined mutagenesis) strain is highly suitable for industrial applications in textiles and biofuels.

This work is licensed under a Creative Commons Attribution 4.0 International License

Keywords
cellulase, bioenergy, rice straw, lignocellulosic biomass, response surface methodology, solid state fermentation