|
چکیده
|
The present study explored the optimization of exoglucanase production from waste cel lulosic biomaterials using microbial cellulases, focusing on enhancing enzyme efficiency through mutagenesis techniques. Research illustrated the hyper-production and quantita tive characterization of an exoglucanase from a thermophilic Aspergillus fumigatus strain via physical and chemical mutagenesis under optimized fermentation conditions. Physical mutagenesis via UV irradiation (15-min exposure) yielded the highest activity (96.57 U/ mL), while chemical mutagenesis with ethyl methane sulfonates (250 µg/mL) resulted in 69.61 U/mL activity. Combined mutagenesis using EMS (250 µg/mL) concentration with 15-min UV exposure significantly enhanced exoglucanase production to 136.19 U/mL as compared to the native enzyme 52.46 U/mL. Among various cellulosic substrates, pea nut shells exhibited superior suitability for exoglucanase production reaching a maximum activity of 202.41 U/mL. Fermentation parameters including pH, temperature, incubation period, and inoculum size were optimized, leading to a substantial increase in exoglu canase activity of 285.28 U/mL using response surface methodology followed by gel filtra tion chromatography. The mutant exoglucanase was characterized by its enhanced activi ties with a higher Vmax (0.6515) and lower Km (0.3142) than those of native enzyme. The characterization has confirmed the temperature and pH tolerance of the mutant enzyme, as well as its tolerance to metal ions and substrate concentrations. This study showed how mutagenesis-driven optimization could provide a means to enhance exoglucanase produc tion from cellulosic biomass, with a rational insight toward enzyme kinetics and applica tions toward bioenergy generation.
|