Engineering of β-glucosidase CaBGL with improved performance in cellulose hydrolysis

β-Glucosidase (BGL) plays a crucial role in lignocellulose utilization by alleviating cellobiose inhibition of cellulases. Incorporation of the BGL from Caldicellulosiruptor sp. F32 (CaBGL) enhanced the overall efficiency of the consolidated bio-saccharification process. To optimize BGL performance under industrial conditions, we established a thermostable green fluorescent protein-based high-throughput screening platform coupled with structure-informed semi-rational design, enabling the generation of functionally enhanced CaBGL mutants. This approach identified mutant M418T, which exhibited more than two-fold catalytic activity compared to that of wild type in both the absence and presence of glucose at various concentrations. In vitro cellulose saccharification showed that M418T increased the saccharification rate coefficient by 43.27 % compared to the wild-type. The mechanisms underlying its improved property were further elucidated through structural analysis and molecular docking. Consequently, this work presents an effective approach for enhancing the performance of CaBGL and demonstrates the potential of a promising catalyst in lignocellulose conversion.