Beta-glucosidase Mutants with Glucose Tolerance and Thermal Stability

The patent applies parameter changes by modifying amino acid residues at specific positions (e.g., E167Q mutation in T. reesei beta-glucosidase) to alter the enzyme's physical and chemical properties. This mutagenesis approach changes the enzyme's tolerance parameters, enabling it to maintain catalytic activity in high glucose concentrations and exhibit enhanced thermal stability without losing its fundamental beta-glucosidase function.

The patent employs parameter changes through site-directed mutagenesis to improve enzyme reliability under industrial process conditions. By changing specific amino acid parameters (e.g., replacing glutamic acid with glutamine at position 167), the enzyme gains enhanced glucose tolerance and thermal stability, thereby maintaining high productivity in demanding industrial applications such as biomass hydrolysis and glycoside synthesis.

The patent applies the extraction principle by expressing the beta-glucosidase enzyme extracellularly in the fungal host T. reesei, thereby extracting the enzyme from the intracellular compartment where it naturally occurs. This allows the enzyme to be secreted into the culture medium, making it easily accessible for industrial applications while preserving its broad substrate specificity for various glycosidic substrates.